2022 Public Health Goal and Contaminants of Emerging Concern Reports — CleanPowerSF Sfpuc Commission, June 28, 2022

London N. Breed
ayo r
Anson Moran
President
Newsha Ajaml
Vice President
Sophie Maxwell
Commissioner
Tim Paulson
Commissioner
Dennis .1. Herrera
General Manager
(ii
San Francisco
,. Water Power Sewer
-"" Services of the San Francisco Public Utilities Commission June 8, 2022
TO: Commissioner Anson Moran, President
Commissioner Newsha Ajami, Vice President
Commissioner Sophie Maxwell
Commissioner Tim Paulson
THROUGH: Dennis J. Herrera, General Manag c5'
Steve R. R. Ritchie, Assistant General Manager, Water Enterprise FROM: Andrew DeGraca, Water Quality Division Director
SUBJECT: 2022 Public Health Goal Report
Attached for your review is the triennial Public Health Goal (PHG) Report that is required under California Health and Safety Code Section 116470(b). The required public hearing is tentatively scheduled to be part of the Commission meeting in September 2022 for the purpose of accepting and responding to public comments on the PHG report.

PHGs are non-enforceable, numerical health protection goals adopted by the California Office of Environmental Health Hazard Assessment (OEHHA). Basically, a PHG is the level of a contaminant in drinking water that does not pose a significant risk to health. The law requires a water system with more than 10,000 service connections, like the San Francisco Water System (SFWS), to prepare a PHG report every three years if any contaminant in drinking water is found at a level above its PHG during the reporting period. When a PHG has not been adopted for a contaminant by OEHHA, the water system must use the Maximum Contaminant Level Goal (MCLG) adopted by the U.S. Environmental Protection Agency (USEPA) for evaluation.

Unlike the enforceable drinking water standards such as Maximum Contaminant Levels (MCLs), with which all public water systems are required to comply, both PHGs and MCLGs are ideal health protection levels that do not consider economic and technical feasibility of treatment. In cases where the PHG or MCLG (in the absence of PHG) of a contaminant that has an established MCL is exceeded, the law requires the water system identify the existing best available technology (BAT) commercially available and estimate the cost to reduce the level of the contaminant to below its PHG, regardless of how minimal the risk may be.

This PHG Report provides the Commissioners and the public with information on water quality, numerical health risks, and actions being implemented/recommended by staff in response to contaminants exceeding PHGs. Overall, the SFWS complies with all enforceable health-based drinking water standards adopted by the State Water Resources Control Board, (SWRCB) and the USEPA between 2019 and 2021 (herein the reporting period). However, three drinking water contaminants were detected at OUR MISSION: To provide our customers with high-quality, efficient and reliable water, power and sewer services in a manner that values environmental and community interests and sustains the resources entrusted to our care.

Water Quality Division
1657 Rollins Rd
Burlingame, CA 94010
T 650.652.3100
F 650.652.3142

2022 PHG Report une 8, 2022
Memo to Commissioners

Page 2 ends

levels above the corresponding PHGs and/or MCLGs during this reporting period.

These are bromate, lead, and total coliform. The following are highlights of the report:

1. Bromate in drinking water is typically a disinfection byproduct from ozonation in the presence of bromide. It is a probable human carcinogen, and it can also cause non-cancer adverse health effects like hyperplasia. This contaminant was detected in the treated water from Harry Tracy Water Treatment Plant (HTWTP), with a maximum running annual average value of 2.1 ppb for the reporting period, above the PHG of 0.1 ppb. The detected levels are typically well below the drinking water standard of 10 ppb. The USEPA and the SWRCB have identified that optimal control of the ozone treatment process is the BAT for reducing bromate formation. In addition to the ongoing practice of using the BAT for ozone dosage control at the HTWTP, staff has implemented a monthly monitoring program since 2020 to track the trends of naturally occurring bromide in the HTWTP's influent. No discussions on any bromate treatment and associated costs is needed.

2. Our latest tap monitoring as well as system monitoring in 2021 continue demonstrating no lead in the system water and tap results meeting the regulatory Action Level of 15 ppb. However, the 90111 percentile lead level of the tap monitoring is above the PHG of 0.2 ppb. Lead is toxic and has multiple chronic health effects including negative neurobehavioral effects in children and hypertension in adults. It also has the potential to cause kidney disease and cancer. Lead enters drinking water primarily through leaching of lead-containing materials in household plumbing and some service lines between water mains and houses. The USEPA and the SWRCB consider BAT for lead in drinking water consists of corrosion control optimization, replacement of identified lead service lines, tap monitoring, and proactive public outreach to educate customers. The SFPUC will continue existing actions and implement additional programs as identified below to assist the customers in reducing lead exposure from drinking water.

Ongoing Actions
• Optimal corrosion control treatment
• Lead abatement activities including replacement with lead-free units for water meters (99.6% completed) and curb stop valves (if found) • Offering low-cost lead tests for City customers and free lead tests for enrollees of the Woman, Infants, and Children Program
• Lead analysis service for San Francisco Department of Public Health (SFDPH) Childhood Lead Prevention Program
• Proactive public outreach efforts to inform consumers of lead's health risks and ways of minimizing lead exposure from drinking water • Prompt removal and replacement of any lead service line upon discovery
• Inventory update of utility-side as well as customer-side lead service lines
• Lead monitoring for daycare centers on San Francisco Unified School District (SFUSD) properties

2022 PHG Report
Memo to Commissioners

Page 3 ends

June 8, 2022
l mplementing Additional Programs:
• Recurring lead monitoring program for K-12 schools and daycare facilities in collaboration with the SFUSD
• Tracking the lead levels in tap water before and after lead service line replacement
• Identifying new Tier 3 sites to recruit volunteers for future lead and copper monitoring under the USEPA's Lead and Copper Rule Revision of 2021. These are homes that had a lead utility service line previously removed and have a galvanized customer service line.

3. Total coli form is a ubiquitous, naturally occurring group of bacteria that is used as an indicator organism for pathogens in drinking water. There is no PHG for total coliform, but the US EPA has a MCLG of zero. No numerical health risk is identified since the actual pathogens are not being measured. The USEPA and SWRCB believe that the detection of this contaminant in drinking water samples does not necessarily present any imminent health risk; however, it may indicate the existence of a potential path of microbial contamination in a drinking water distribution system. The SFPUC is already practicing State approved BA Ts to prevent and minimize coliform contamination. These BA Ts consist of conducting proper pipeline flushing and disinfection, implementing effective cross-connection control program, maintaining healthy disinfectant residuals in the distribution system, and performing ongoing water quality monitoring for the distribution system. There is no additional treatment that can guarantee always meeting the MCLG of zero. Per PHG Guidance published by the Association of California Water Agencies, the MCLGs of zero was not exceeded for microbial contaminants including Cryptosporidium, Giardia lamblia, Legionella, and viruses since the SFPUC uses the required treatment technique to meet the drinking water standard.

In summary, the benefits of reducing naturally occurring contaminants are minimal, whereas zero MCLG is practically unattainable. The SFPUC has already implemented the BA Ts for the three contaminants identified in this report and will continue existing programs to help customers reduce exposure to these contaminants in drinking water.

Encl.: 2022 PHG Report
Cc: Manouchehr Boozarpour, WQD
Eddy So, WQD
Records Management, WQD
Vladimir Rakhamimov, SWRCB
Bill Teahan, CDD
June Weintraub, SFDPH
Nicole Sandkulla, BA WSCA
San Francisco Water System
2022 Public Health Goals Report
Prepared by:

San Francisco Public Utilities Commission
Water Quality Division
1657 Rollins Road
Burlingame, CA 94010
Date:

June 10, 2022

ii
(Thi
s page is intentionally left blank)
iii
Acronyms and Abbreviations
ACWA Association of California Water Agencies
BAT Best available technology
CHSC California Health and Safety Code
DBP Disinfection byproduct
DLR Detection Limit for the Purposes of Reporting
HTWTP Harry Tracy Water Treatment Plant
LUSL Lead user service line
MCL Maximum Contaminant Level
MCLG
MGD
Maximum Contaminant Level Goal
Million gallons per day
MRL
O&M
Method reporting limit
Operations and maintenance
OEHHA Office of Environmental Health Hazard Assessment
PHG Public Health Goal
ppb parts per billion
SFDPH San Francisco Department of Public Health
SFGW San Francisco Groundwater Project
SFPUC San Francisco Public Utilities Commission
SFWS San Francisco Water System
SVWTP Sunol Valley Water Treatment Plant
SWRCB State Water Resources Control Board
USEPA United States Environmental Protection Agency
iv
San Francisco Water System
2022 Public Health Goals Report
Table of Contents
I. Introduction ........................................................................................................................ 1 A. Regulatory Requirements ............................................................................................. 1 B. PHG and MCL ............................................................................................................... 1 C. Guidelines ..................................................................................................................... 2 D. Water Supply to SFWS………………………………………………………………..2
II. Elements of the PHG Report ........................................................................................... 2 A. Target Drinking Water Contaminant Levels ................................................................ 2 B. Health Risks………………………………………………………………………….. 3
C. Best Available Technologies (BATs) and Cost Estimate ............................................. 4 D. SFPUC Programs .......................................................................................................... 5 III. Water Quality Data and Analysis .................................................................................. 5 A. Contaminants Detected above PHGs/MCLGs .............................................................. 5 B. Contaminants that Meet Requirements for Treatment Techniques .............................. 6 IV. Evaluation of Contaminants Exceeding PHGs or MCLGs ......................................... 6 A. Bromate ......................................................................................................................... 6 B. Lead ............................................................................................................................... 7 C. Total Coliform Bacteria .............................................................................................. 12 V. Recommendations for Further Actions ........................................................................ 13 v
Tables
1 Contaminants Detected Above PHGs/MCLGs .......................................................................5 Figures

1. SFPUC Water Quality Targets vs. PHGs/MCLGs and MCLs ..................................................... 3

2. Potential Contributors to Lead in Tap Water from Household Plumbing ..................................... 8 Attachments
A Excerpt from California Health and Safety Code, Section 116470(b)- (f) B Health Risk Information for Public Health Goal Exceedance Reports C SFWS Water Quality Reports – 2019, 2020, and 2021
(Thi
s page intentionally left blank)
2022 Public Health Goals Report San Francisco Water System 1 San Francisco Water System
2022 Public Health Goals Report
This
report is divided into the following sections:

I. Introduction
II. Elements of the PHG Report
III. Water Quality Data and Analysis
IV. Evaluation of Contaminants Exceeding PHGs or MCLGs
V. Recommendations for Further Actions
I. Introduction
A. Regulatory Requirements
California Health and Safety Code (CHSC) §116470(b) (Attachment A) requires public water systems with more than 10,000 service connections prepare a brief written report by July 1 every three years for contaminants that exceed the applicable public health goals (PHGs) in drinking water. The report, which is referred to as the PHG report herein, is to provide consumers with the following information:
• Each contaminant that exceeds the applicable PHG in drinking water • Numerical public health risk, including the risk category for the contaminant • Any commercially available best treatment information and associated cost estimates to reduce the contaminant to the PHG level
• Actions already taken, or intended to be taken, by the water system to reduce the contaminant in drinking water
Water systems are required to use applicable maximum contaminant level goal (MCLG) adopted by the United States Environmental Protection Agency (USEPA) if no PHG is available. While the primary drinking water standards, which are expressed in maximum contaminant levels (MCLs) or treatment technique (TT), are enforceable, both the PHGs and the MCLGs are not.

Systems preparing the PHG report are required to hold a hearing for the purpose of accepting and responding to public comment on the report.

B. PHG and MCL
PHGs are published by the California Office of Environmental Health Hazard Assessment (OEHHA) to support the MCL development effort of the State Water Resources Control Board (SWRCB). A PHG is the concentration of a contaminant in drinking water that poses no significant health risk if consumed for a lifetime, whereas the MCL is set as close to the PHGs (or MCLGs) as is economically and technologically feasible.
2022 Public Health Goals Report San Francisco Water System 2 A PHG is based solely on public health risk using current risk assessment principles and methods, without consideration of practical risk-management factors, which are used by the SWRCB to set enforceable drinking water standards. MCLG is determined by the USEPA using a similar process. However, the USEPA sets the MCLGs of all carcinogens at zero, even though the goal of zero is difficult or impossible to meet.

Therefore, adopted MCLs are the criteria for regulatory compliance determination, not those proposed or possible in the future and certainly not MCLGs or PHGs.

C. Guidelines
San Francisco Public Utilities Commission (SFPUC) staff prepared its first PHG report for the San Francisco Water System (SFWS) in 2004 without any regulatory guidance. The Association of California Water Agencies (ACWA) developed guidelines to help water systems prepare the PHG report in 2007. The guidelines, updated every three years, provide structured approach to enhance consistency in PHG report preparation. The latest ACWA guidelines were used in the preparation of this 2022 PHG.

D. Water Supply to SFWS
The SFWS’s drinking water supply is from the wholesaler, San Francisco Regional Water System (SFRWS), supplemented with a small contribution from its own local groundwater sources. Although both SFWS and SFRWS are operated by the SFPUC, these two water systems are separately permitted by the SWRCB and each has its own regulatory responsibilities to fulfill. All treatment and watershed management of the surface water sources are the responsibility of the SFRWS, whereas the SFWS is responsible for the operations and maintenance of the distribution system and local groundwater wells within the City and County of San Francisco. As a wholesaler, the SFRWS delivers drinking water, which is typically 1 a blend of unfiltered
water from Hetch Hetchy Reservoir and filtered water from two treatment plants using local water sources.

The contribution of each water source in the blend varies throughout the year.

II. Elements of the PHG Report
This section discusses the key elements of the report that will help explain the significance of a PHG exceedance. These include target drinking water levels, health risks, identified best available technology (BAT) and cost estimates, and SFPUC programs. Only contaminants that have an existing primary drinking water standard and were “detected” at a level that “exceeds” the existing PHG or MCLG need to be included in the report. There are a few constituents, including total trihalomethanes and five haloacetic acids, that are routinely detected in water systems at levels usually well below the MCLs for which no PHG nor MCLG exists. These will be addressed in future reports after a PHG or a MCLG has been adopted.

A. Target Drinking Water Contaminant Levels
To ensure that customers receive high-quality drinking water, the SFPUC sets its own operational water quality targets at levels more stringent than the MCLs. These operational target levels help SFWS and

1 Although the SFRWS has new groundwater sources approved by the SWRCB during the reporting period, these groundwater wells are designed to be used during drought conditions. In 2021, four of these wells together contributed to less than 0.07% of the overall SFRWS’s supply. 2022 Public Health Goals Report San Francisco Water System 3 SFRWS prevent MCL violations. Figure 1 illustrates the relationship between the SFPUC’s water quality targets, PHGs/MCLGs, and MCLs.

Figure 1. SFPUC Water Quality Targets vs. PHGs/MCLGs and MCLs Contaminants that have existing MCLs or TTs and have confirmed detections in exceedance of the applicable PHGs or MCLGs (if no PHGs available) in drinking water are included. However, there are two terms worthy of further explanation:

1. Detection Limit for Reporting Purposes
Along with each MCL, the SWRCB also adopted a corresponding Detection Limit for Purposes of Reporting (DLR) to help determine a water system’s compliance with the drinking water standards. When a contaminant has a confirmed level above the DLR, it is conceived as “detected” according to the drinking water requirements in Title 22 of the California Code of Regulations (Title 22). Per SWRCB guidance and procedure on compliance reporting, results that are reported below the DLR would be treated as zero for calculation purpose. A similar approach was used for PHG comparison in this report.

2. Exceedance
There are no regulations that relate to data handling for complying with PHGs. According to ACWA guidelines and consistent with the procedure acceptable to the SWRCB for MCL compliance determination, this report follows the same approach in evaluating water quality data for PHG comparison.

For example, if Title 22 of the California Code of Regulations or the SWRCB guidance specifies that the average of a group of samples be compared to the MCL for compliance purposes, the same averaging approach is used to determine detections for comparison to the PHG or MCLG. If wells are blended or treated before delivery to the system, the judgment as to whether there was a “detection exceeding the MCLG or PHG” is be based on the “point of entry” data just as for compliance with MCLs. As in all cases of reporting results to the SWRCB, the analytical results are rounded to reflect appropriate number of significant figures matching the corresponding PHG or MCLG.

B. Health Risks
The OEHHA evaluates toxicological data from scientific literature to assess health risks for each contaminant in categories (Attachment B) including, among others, the following:

2022 Public Health Goals Report San Francisco Water System 4 • Carcinogenic: capable of producing cancer.
• Cardiovascular toxicity: adverse effects on the structure or function of the heart or the vascular system following exposure to a chemical substance.
• Developmental toxicity: adverse effects on a developing organism that may result from exposure prior to conception (either parent), during prenatal development, or postnatally to the time of sexual maturation. Adverse developmental effects may be detected at any point in the life span of the organism. The major manifestations include (1) death of the developing organism, (2) structural abnormality (birth defects), (3) altered growth, and (4) functional deficiency. • Neurotoxicity: capable of adversely affecting or destroying parts of the nervous system or interfering with nerve signal transmission. Effects may be reversible (for example, effects on chemicals that carry nerve signals across gaps between nerve cells) or irreversible (for example, destruction of nerve cells). • Reproductive toxicity: adverse effects on the reproductive system of females or males. The toxicity may cause changes to the female or male reproductive organs, the regulating endocrine system, or pregnancy outcomes.

The OEHHA calculates numerical risks associated with a contaminant’s non-carcinogenic and carcinogenic effects, if any, on human health. The PHG is then developed as a public health-protective concentration based on the most sensitive health effects. For contaminants with non-carcinogenic effects, PHGs are set at concentrations at which no known or anticipated adverse health effects occur. For carcinogens, PHGs are set at concentrations that do not pose a significant risk to health (usually less than 1 in 1,000,000 additional cases resulting in adverse health effects). By regulation, OEHHA cannot set a PHG at zero. However, the USEPA considers no safe level of exposure to carcinogens and sets MCLGs for carcinogens at zero.

C. Best Available Technologies (BATs) and Cost Estimate For drinking water, both the USEPA and the SWRCB have specified BATs that have been determined to be the best available methods for reducing contaminant levels to MCLs. Costs can be readily estimated for such technologies. However, since most PHGs and MCLGs are set much lower than the corresponding MCLs (and some MCLGs are set at zero), it is not always possible to determine what treatment could further reduce a contaminant down to the PHG or MCLG level. Estimating the cost to reduce a contaminant to absolute zero is impossible, as it is not technically feasible to verify by existing analytical methods that the level has truly been lowered to zero. Only very preliminary cost estimates, if applicable, are required in PHG reports.

ACWA has compiled unit cost estimates (dollars per thousand gallons treated) for BATs from various sources.

For presenting cost estimates, ACWA guidelines suggest including both total project cost and the cost per customer. As the amount of water used by each SFWS customer varies, this report presents costs in a percent increase of a customer’s water bill. Since other wholesale customers uses approximately two-thirds of SFRWS’s surface water supply, only one third of estimated costs for surface water treatment, if any, will be assigned to SFWS retail customers. Any estimated costs of additional treatment, if needed, for San Francisco’s own groundwater sources will be solely borne by SFWS retail customers.

It should be noted that installing a treatment technology to reduce already low levels of a single contaminant could have unexpected and adverse consequences on other aspects of water quality.

2022 Public Health Goals Report San Francisco Water System 5 D. SFPUC Programs
Other than the applicable BATs, the SFPUC also engages in various voluntary and mandatory programs to protect public health and maintain drinking water quality. These programs typically focus on source water protection, public outreach, treatment chemical quality assurance, and optimization of treatment and operations.

III. Water Quality Data and Analysis
Drinking water regulations require compliance with MCLs or TT but not PHGs. Thus, the logical approach for determination of PHG or MCLG exceedance would be to use the same procedures and requirements specified in Title 22 for determining compliance with MCLs. All water quality data collected for compliance monitoring between January 1, 2019 and December 31, 2021 (herein the Reporting Period) for purposes of determining compliance with drinking water standards were considered. These data include those collected at the entry points to the SFRWS as well as within the SFWS’s own distribution system. Concentrations of analytes detected above DLRs in treated water delivered to SFWS customers in 2019, 2020, and 2021 were summarized in the corresponding Annual Water Quality Reports (a.k.a. Consumer Confidence Reports) in Attachment C
A. Contaminants Detected above PHGs/MCLGs
Table 1 shows the monitoring results of the three contaminants that exceed the applicable PHGs or MCLGs during the Reporting Period.

Table 1. Contaminants Detected above PHGs/MCLGs in SFWS Contaminant Unit MCL DLR PHG MCLG Maximum
Detection
Bromate ppb 10 1 0.1 0 2.1(a)
Lead ppb 15(b) 5 0.2 0 7(c)
Total coliform P/A 5% N/A N/A 0 1%(d)
Notes: (a) This is the maximum running annual average value (b) Lead does not have MCL; 15 ppb is the Action Level (AL), of which the exceedance is based on the 90th percentile lead result measured at customer taps.
(c) This is the 90th percentile lead result.
(d) This is the maximum monthly percentage of total coliform positive results.

Key: N/A = not available P/A = Presence/Absence ppb = parts per billion • Bromate exceeding its PHG in treated water samples HTWTP effluent in the reporting period. • Lead exceeding its PHG in customer tap samples collected by the SFWS in 2021 Lead and Copper Rule monitoring; it was non-detect in the distribution system and in the SFRWS’s source water. 2022 Public Health Goals Report San Francisco Water System 6 • Total coliform (a bacteriological indicator) exceeding its MCLG in the SFWS distribution system in 2020.

B. Contaminants that Meet Requirements for Treatment Techniques For pathogenic microorganisms (i.e., Cryptosporidium, Giardia lamblia, Legionella, heterotrophic bacteria, and viruses) that are regulated under the Surface Water Treatment Rule and Long-Term 2 Enhanced Surface Water Treatment Rule, the drinking water standard is met if the water supplier uses specified treatment techniques. The OEHHA does not establish PHG for pathogenic microorganisms. Although the MCLG for the microorganism contaminants is zero, the USEPA does not mandate monitoring because there are limitations in existing analytical methods that can specifically point to an individual infective pathogen. The SFPUC performed voluntary monitoring of Giardia lamblia and Cryptosporidium for the SFRWS and SFWS during the Reporting Period. These monitoring results are for research and operational purposes and not for compliance purposes. These contaminants are considered to not have exceeded their MCLGs because the SFPUC uses the required TT.

Similarly, there are no primary drinking water standards in MCL values for lead and copper, but the corresponding regulations establish optimized corrosion control treatment as TT along with tap monitoring results not to exceed the applicable ALs (i.e., 15 ppb for lead and 300 ppb for copper).

IV. Evaluation of Contaminants Exceeding PHGs or MCLGs
During the Reporting Period, San Francisco’s drinking water has met all MCLs and TTs adopted by the USEPA and the SWRCB. However, bromate and lead exceeded the corresponding PHG and total coliform exceeded the MCLG. The following sections discuss water quality monitoring results and the applicable health goals, associated health risks, identified BATs and preliminary cost estimates, if any, and programs in place or to be implemented by the SFPUC to address these contaminants.

A. Bromate
The OEHHA established a PHG of 0.1 ppb for bromate, which is 1% of the MCL (10 ppb). Bromate salts are used as a food ingredient and a neutralizing agent in hair products. Bromate is usually not found in water sources. In drinking water, bromate is typically formed as a disinfection byproduct from ozonation when naturally occurring bromide reacts with ozone. The HTWTP uses ozone for primary disinfection and pre- oxidation.

1. SFPUC Water Sample Results
Bromate is subject to monthly monitoring, and compliance with the MCL is determined quarterly based on the annual average results. It has been detected in the treated water at the HTWTP effluent during the reporting period. Bromate was non-detect in 2019. Starting in 2020, the method of analysis was changed with a lower detection limit. The highest running annual average values were at 2.1 ppb for both 2020 and 2021. Though exceeding the PHG of 0.1 ppb, these detections are well below the MCL of 10 ppb. 2022 Public Health Goals Report San Francisco Water System 7 2. Health Risk Category and Level
Bromate is classified as a probable human carcinogen. Acute symptoms of bromate ingestion include nausea, vomiting, diarrhea, central nervous system depression, tinnitus, deafness, and renal failure. The OEHHA primarily identifies hyperplasia2 as a non-cancer risk associated with bromate in drinking water. Cancer risk associated with lifetime consumption of water at the PHG translates into one per one million excess cancer cases. Cancer risk at the MCL is approximately one per ten thousand excess cancer cases. However, bromate is still permitted in use as a food additive in raw ingredients (such as flour), though it is largely converted to bromide in the baking process.

3. BATs and Treatment Cost
Bromate is a disinfection byproduct formed when the source water containing bromide is subject to ozonation treatment at the HTWTP. Although it is technically possible to remove bromate after formation using several treatment approaches, such as activated ferrous iron addition, UV irradiation, or membrane and anion exchange resins
3, these methods have been evaluated primarily at bench-scale and pilot level. Information on full-scale application and associated treatment and O&M costs are rare. In fact, the USEPA and the SWRCB have both identified optimized control of the ozone treatment process as the BAT for reducing bromate formation. Therefore, no additional BAT and associated cost estimate for bromate is evaluated in this report.

4. SFPUC Programs
The SFPUC began a one-year special monthly monitoring program to track the bromide level in the raw water supply to the HTWTP, as recommended in the 2019 PHG report. The one-year monitoring has been extended and become a routine operational monthly monitoring effort. The 2020-2021 data showed that bromide levels in the raw water were generally low at an average of 22 ppb with a range of 18 ppb -30 ppb.

In 2015, a Long-Term Improvements Project was completed at the HTWTP that allows the SFPUC to optimize ozone dosage and residual management to meet the disinfection byproducts requirements. This major improvement project included new ozone generators as well as flow control upgrades to improve ozone generation, ozone feed system, ozone dose adjustments, and ozone residual measurements.

Together with the existing watershed management/protection program, these monitoring and ozone optimization efforts will continue to be the most efficient and effective treatment approach for the SFPUC to minimize the formation of bromate.

B. Lead
The PHG for lead is 0.2 ppb, which is below the DLR of 5 ppb. The SWRCB adopted AL of 15 ppb for lead in 1995 and requires that lead concentrations in 90% of water samples collected at customer taps not to exceed the AL.
2 Hyperplasia is an enlargement of an organ or tissue caused by an increase in the amount of cell number. OEHHA concluded this based on male rat data in the DeAngelo et al. (1998) study. 3 Health Canada, Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Bromate, October 2016
2022 Public Health Goals Report San Francisco Water System 8 Lead enters drinking water primarily through leaching of lead-containing materials in household plumbing (Figure 2). These materials include lead-based solder used to join copper pipes, brass and/or chrome-plated brass faucets, lead pipe connections from homes to water mains (herein referred to as lead user service line, or LUSL), brass/bronze water meters, brass/bronze curb valves, and brass/bronze corporation valves. Corrosion of these materials in a plumbing system can contribute to lead in household drinking water. Note that CHSC §116875 and the Safe Drinking Water Act of 2014 require that pipes, fittings, fixtures, solder, and flux used in plumbing systems must meet the amended definition of “lead-free”.4 However, older lead-containing materials remain in many households.

Figure 2. Potential Contributors to Lead in Tap Water from Household Plumbing There are other lead sources than drinking water present in the environment. For example, lead-based paint was widely used in home painting before 1977, and is still the major source of lead exposure to children in San Francisco. The San Francisco Department of Public Health (SFDPH) visits homes of children with elevated blood lead levels to investigate potential environmental causes and inspect for the presence of lead in the home environment. The SFDPH investigations of lead-exposed children in San Francisco have found that the most

4 Plumbing components are considered “lead-free” if the weighted average lead content of the component’s wetted surface area is not more than 0.25%.
2022 Public Health Goals Report San Francisco Water System 9 common sources of environmental lead are lead-based paint, lead-contaminated soil, and take-home exposure of adults employed in the construction industry.5

1. SFPUC Water Sample Results
Lead w
as not detected in raw water sources to the SFRWS and water supply to the SFWS. The SFPUC conducted the triennial lead and copper monitoring at SFWS customer taps in 2021 according to the schedule approved by the SWRCB. The results showed that the AL for lead was not exceeded. However, lead levels in 10 of 72 tap monitoring results were above the DLR of 5 ppb, and thus perceived as exceeding the PHG of 0.2 ppb. The probable lead source in these tap samples is household plumbing. It is likely that some residences have higher lead levels in their tap water than others because of differences in plumbing materials.

2. Health Risk Category and Values
Lea
d has multiple toxic effects on human body. The carcinogenic risks are considered smaller than the risks for chronic toxicity, which includes negative neurobehavioral effects in children, hypertension in adults, potential to cause kidney disease. The most sensitive risk is the reduction of Intelligence Quotient (IQ) points in children. The public health goal of 0.2 ppb was determined from a maximum daily lead intake of 2.86 micrograms per day, which corresponds to a decrease of one IQ point in children.

3. BATs and Cost
The S
WRCB considers optimizing corrosion control as the BAT for reducing lead in drinking water and approved the SFPUC’s use of pH adjustment as the optimal corrosion control treatment. The SWRCB requires that a minimum pH value of 8.2 be maintained throughout the transmission and distribution systems.

Because the SFWS continues to meet the AL for lead and operates the water system with pH greater than 8.2, the SWRCB requires no additional BATs.

In addition to corrosion control optimization, the SWRCB also requires water systems implement a LUSL replacement program that comprise (i) an inventory of service lines identifying lead, unknown, and galvanized steel materials, and (ii) a replacement schedule that includes both system-side and customer-side service lines.

Although this is not considered a BAT, the goal is to help further reduce the customer exposure to lead in drinking water.

4. SFPUC Programs
In conj
unction with existing tap monitoring and optimized corrosion control treatment, the SFWS has also implemented the following actions with the goal of reducing lead exposure to San Francisco residents.

Replacement of Lead Components
5 See SFDPH report “Two Decades Protecting San Francisco Children from Lead Exposure” at Department of Public Health -Childhood Lead Prevention Program (sfdph.org).
2022 Public Health Goals Report San Francisco Water System 10 1980s Removed approximately 7,000 lead service lines in the distribution system. 1983 Discontinued “leaded” water main joints in the distribution system. 2003 Began replacing curb stop valves with lead-free units when found. 2008 Began replacing water meters with lead-free units and now over 99.6% complete.

Lead User Service Line (LUSL) Inventory and Replacement Since 2010, the plumbing components used for human consumption in California have been “lead-free”.

However, there are minor fittings known as lead whips in older parts of the SFWS. If a lead whip is found, it will be quickly replaced in coordination with the customer. As of May 1, 2022, a total of 31 lead whips was found and replaced.

In 2018, the SFWS completed an inventory of LUSL in accordance with Senate Bill 427 (2017), which does not apply to water lines on customer’s side of the meter or the meter itself, but include lead goosenecks (also known as lead whips) associated with the user service line on the water system side. The LUSL inventory reported to the SWRCB had the following findings:
• No lead pipelines were identified.
• 10,912 service lines were made of unknown material.
• 4,988 galvanized6 steel service lines that may contain short (2 to 3 feet) section of lead whip connectors on the water main.

This initial service line inventory was subsequently refined and updated in 2019 and 2020 based on additional information gathered after 2018.

In June 2020, the SFPUC submitted a 10-year lead component replacement schedule to the SWRCB for the estimated total of 1,578 galvanized steel services lines that may have lead whips. The schedule includes field inspection to confirm the unknown material service lines. If a galvanized service line is found or the unknown material cannot be verified, the service line is scheduled for replacement. The SFWS created a Lead Service Line Replacement Program with a customer lookup map, which is posted on SFPUC’s website (sfpuc.org/lead). A customer can use the map to identify if the add ress has an unknown or galvanized service line. The LUSL will not be replaced until the customer has been given lead health information fact sheets, building flushing instructions, and water pitcher filter with 6-month supply of filters.

In July 2021, the 10-year
lead component replacement schedule was updated with the number of unknowns and galvanized services that remained to be inspected. New changes also reflected that customers in disadvantaged neighborhood areas would be distributed equitably in the monthly field inspection and replacement schedule. As of May 2022, about 2,904 field inspections remain with 1,031 galvanized services

6 Total 5,218 service lines were possibly made of galvanized steel, brass, or wrought iron material. Older galvanized pipelines material can corrode, which could potentially allow any lead contained therein to accumulate over time and be released after the lead source (i.e., lead whip) is removed. 2022 Public Health Goals Report San Francisco Water System 11 confirmed and planned for replacement. It is anticipated that the field inspection and inventory of unknown lines will be completed by Fall 2022.

Between July 2019 and May 2022, SFPUC staff conducted a pilot study evaluating the lead levels at residences in SFWS where 158 LUSLs (including the 31 lead whips) were subsequently replaced. A total of 36 participants volunteered for the study, of which the results indicated that lead levels in tap samples after LUSL replacement increased slightly and then dropped to levels lower than the AL. Some of these participants still have detectable lead results in their first 1-liter samples, suggesting that the household plumbing is still a contributor to the lead detected in the tap water. These are consistent with industry findings. See Attachment C for the SFWS report on “Impact of Lead Components on Household Lead Levels at the Tap”, dated March 2022.

In addition to the above lead reduction activities, the SFPUC is working on the development of the following to comply with the USEPA’s 2021 Lead and Copper Rule Revision:
• Identification of new Tier 3 sites to recruit volunteers for future lead and copper monitoring. These are homes that had a lead utility service line removed and have a galvanized customer service line. • Inventory of customer service line materials (completed inventory of 5,027 pipelines as of May 2022 and 406 are galvanized service lines)
Public Outreach and Education
The SFPUC has long taken a proactive approach to educating customers about lead in drinking water, its health effects, and ways to reduce lead exposure in drinking water. Below are highlights of public outreach activities:
1980 Conducted free lead tests of drinking water taps at the San Francisco Unified School District. 1994 Began providing “Lead Test for a Fee” for consumers, testing tap water for a nominal fee. 1996 Began sending customer-focused communications regarding lead issues in bill inserts and annual Water Quality Reports.

Participated in San Francisco Department of Public Health’s (SFDPH) Childhood Lead Prevention Program to provide laboratory services and water sampling assistance to help investigate the lead sources for cases of high blood levels in children residing in the City. 1998 Began offering free lead tests for Women, Infants & Children program enrollees. 2000-
2010
Provided lead-free faucets to childcare centers and public schools in San Francisco at no cost and offered significantly discounted lead-free faucets to city residents via annual sales at street fairs.
2017-
2019
Assisted 198 public and private K-12 schools including pre-school facilities on public school properties in sampling and analysis of lead in drinking water. 2022- Assist San Francisco Unified School District in completing lead sampling at childcare centers 2022 Public Health Goals Report San Francisco Water System 12 Present by January 2023 and develop a long-term, recurring lead monitoring program for the K-12 schools.

C. Total Coliform Bacteria
The bacteriological quality of drinking water is generally expressed in terms of total coliform and fecal coliform like E. coli. Total coliform is naturally present and ubiquitous in the environment, whereas E. coli are bacteria whose presence indicates that the water may be contaminated with human or animal wastes. Total coliform is used as a proxy measure of bacterial contamination because it can be easily monitored and analyzed. The MCL for bacteriological quality in drinking water has been changed in 2021 as follows:
• No more than 5.0% monthly total coliform samples are positive; and • The total number of samples showing E. coli positive should be zero during the reporting year.

The OEHHA has not set a PHG for either total coliform or E. coli, but the USEPA has established a MCLG of zero for both.

1. SFPUC Water Sample Results
Due to the ubiquitous nature of total coliform, a public water system, no matter how well it is being operated and maintained, will have an occasional coliform-positive result. In fact, it is not possible to assure that a water system will never have a total coliform positive sample. For the SFWS, the maximum monthly total coliform positive samples are 0%, 1%, and 1% in the years of 2019, 2020, and 2021, respectively. No E. coli was detected in any of the coliform-positive samples. These monitoring results indicate that the SFWS complied with the applicable MCLs for the 3-year reporting period, but exceeded the MCLG of zero percent for total coliform in years 2020 and 2021.

2. Health Risk Category and Values
The detection of total coliform in drinking water samples indicates the possible presence of pathogen contamination pathways in the distribution system; however, total coliform by itself is not generally considered harmful. The numerical health risk cannot be determined since the actual pathogens are not being measured. On the other hand, human pathogens in these wastes can cause short-term effects, such as diarrhea, cramps, nausea, headaches, or other symptoms. They may pose a greater health risk for infants, young children, some of the elderly, and people with severely compromised immune systems.

3. BATs and Cost
Exceeding 0% coliform bacteria in any month, in and of itself, would not normally constitute the need for any new or additional treatment or action. There is no action that could be taken to ensure zero-percent coliform every single month. The SWRCB has specified BATs for MCL compliance. These BATs have been adopted by the SFPUC for the operations and maintenance of the SFWS. The costs associated with the implementation of these BAT measures are already budgeted as annual expenses in the operations of the SFWS. One method for reducing bacteriological contamination is to maintain effective disinfectant residuals in the water distribution system. However, increasing chlorine residual levels in the SFWS drinking water at the SFRWS’s 2022 Public Health Goals Report San Francisco Water System 13 treatment plants could likely increase the levels of disinfection byproducts, which might have adverse health consequences.

4. SFPUC Programs
Positive total coliform samples may indicate a potential problem in the distribution system. A routine sample showing coliform positive usually triggers the collection of three repeat samples according to the applicable regulations. If the repeat samples showed total coliform positives, usually follow-up investigation and mitigation may be required. In response to the reported total coliform positive results, the SFWS implemented the protocol consisting of follow-up monitoring, investigation, and mitigation, as needed. No trend or pattern had been identified that suggested the presence of a contamination source or there was a systemwide problem.

The SFWS maintains an effective distribution system maintenance program, which comprises the following elements:
• Water main flushing and disinfection
• Reservoir and storage tank inspection and cleaning
• Cross-connection control and backflow prevention
• Routine chlorine-residual monitoring and boosting
• Maintaining positive water pressures throughout the distribution system. • Continuous sanitary practices such as capping open ends of pipes in storage yard, etc.

In conjunction with the SFRWS’s watershed controls at the Hetch Hetchy Reservoir and local water sources, the above measures help reduce the potential for bacteriological contamination at the SFWS’s water sources and the distribution system.

V. Recommendations for Further Actions
In accordance with the OEHHA literature,7 a PHG is not a boundary line between a “safe” and “dangerous” level of a contaminant. Drinking water is considered acceptable for public consumption, even if it contains contaminants at levels exceeding the PHG, provided the MCLs are met.

The benefits of reducing the naturally occurring contaminants are minimal if their levels are well below their corresponding MCLs. The SFPUC will continue monitoring for the bromide level in the influent and optimizing the ozone dose to minimize bromate formation at the HTWTP.

The major source of lead in tap water is the plumbing fixtures at customer premises, albeit that the presence of lead service lines may also contribute to the lead level in drinking water. The most effective actions that the SFPUC can take to reduce customer’s exposure to lead in drinking water are to maintain optimized corrosion 7 OEHAA, Guide to Public Health Goal for Chemicals in Drinking Water, 2022. 2022 Public Health Goals Report San Francisco Water System 14 control treatment, and continue existing lead abatement and public outreach efforts. Identifying and replacing service lines and components of unknown and galvanized materials will also help ensure that lead is not introduced into drinking water.

Since the SFPUC is already practicing the BATs for total coliform and E. coli, no additional treatments are required to meet the MCLG of zero.

In summary, the SFPUC will continue existing surveillance and monitoring programs in a proactive manner to control and reduce contaminants entering the water supply to the SFWS.

2022 Public Health Goals Report San Francisco Water System Attachmen
t A
Excerpt from California Health and Safety Code, Section 116470(b)-(f) Excerpt from California Health and Safety Code: Section 116470(b)—(f) (b) O
n or before July 1, 1998, and every three years thereafter, public water systems serving more than 10,000 service connections that detect one or more contaminants in drinking water that exceed the applicable public health goal, shall prepare a brief written report in plain language that does all of the following:
(1) Ide
ntifies each contaminant detected in drinking water that exceeds the applicable public health goal.
(2) Disc
loses the numerical public health risk, determined by the office, associated with the maximum contaminant level for each contaminant identified in paragraph (1) and the numerical public health risk determined by the office associated with the public health goal for that contaminant.
(3) Ide
ntifies the category of risk to public health, including, but not limited to, carcinogenic, mutagenic, teratogenic, and acute toxicity, associated with exposure to the contaminant in drinking water, and includes a brief plainly worded description of these terms.
(4) Des
cribes the best available technology, if any is then available on a commercial basis, to remove the contaminant or reduce the concentration of the contaminant. The public water system may, solely at its own discretion, briefly describe actions that have been taken on its own, or by other entities, to prevent the introduction of the contaminant into drinking water supplies.
(5) Esti
mates the aggregate cost and the cost per customer of
utilizing the technology described in paragraph (4), if any, to reduce the concentration of that contaminant in drinking water to a level at or below the public health goal.
(6) Brief
ly describes what action, if any, the local water purveyor intends to take to reduce the concentration of the contaminant in public drinking water supplies and the basis for that decision. (c) P
ublic water systems required to prepare a report pursuant to subdivision (b) shall hold a public hearing for the purpose of accepting and responding to public comment on the report. Public water systems may hold the public hearing as part of any regularly scheduled meeting.
(d)
The department shall not require a public water system to take any action to reduce or eliminate any exceedance of a public health goal. (e)
Enforcement of this section does not require the department to amend a public water system's operating permit.
(f)
Pending adoption of a public health goal by the Office of Environmental Health Hazard Assessment pursuant to subdivision (c) of Section 116365, and in lieu thereof, public water systems shall use the national maximum contaminant level goal adopted by the United States Environmental Protection Agency for the corresponding contaminant for purposes of complying with the notice and hearing requirements of this section.
2022 Public Health Goals Report San Francisco Water System

Attachmen
t B
Health Risk Information for Public Health Goal Exceedance Reports DRAFT – FOR REVIEW ONLY

OFFICE OF ENVIRONMENTAL HEALTH HAZARD ASSESSMENT
Public Health Goals
Health Risk Information
for Public Health Goal
Exceedance Reports
February 2022
Pesticide and Environmental Toxicology Branch
Office of Environmental Health Hazard Assessment
California Environmental Protection Agency
Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2022 1
Health Risk Information for
Public Health Goal Exceedance Reports
Prepared b
y
Office of Environmental Health H azard Assessment
Calif
ornia Environmental Protection Agency
February 2022
NEW for the 2022 Report: New in this document are an updated Public Health Goal (PHG) for
1,2-dibromo-3-chloropropane (DBCP) and newly established PHGs for the trihal
omethanes bromodichloromethane, bromoform, chloroform, and dibrom
ochloromethane.

Background: Under the Calderon-Sher Safe Drinking Water Act of 1996 (the Act), publi
c w
ater systems with more than 10,000 service connections are required to prepare a repor
t every three years for conta minants that exceed t heir respective PHGs.1 This docum
ent contains health risk information on regulated drinking water contami
nants to assist public water system s in preparing these reports. A PHG is the concent
ration of a contaminant in drinking water that poses no significant health risk if consumed for a lifetime. PHGs are developed and published by the Off ice of Environmental Health Hazard Assessment (OEHHA) u sing current risk assessment principl
es, practices and methods.2
The water system
’s report is required to identify the health r isk category (e.g., carcinogen
icity or neurotoxicity) associat ed with exposure to each regulated contaminant in drinking water and to include a brief, plainly wor ded description of these risks.

The report is also required to disclose the numerical public health risk, if available, associated w
ith the California Maximum Contaminant Level (MCL) and with the PHG for each
cont
aminant. This health risk information document is prepared by OEHHA every three year
s to assist the water systems in providing the required information in their reports.

1 Health and Safety Code Section 116470(b)
2 H
ealth and Safety Code Section 116365
Off
ice of Environmental Health Hazard Assessment
Water Toxicology Section
February 2022 2
Numerical health risks: Table 1 presents health risk categories and cancer risk values for chemical contaminants in drinking water that have PHGs.

The Act requires that OEHHA publish PHGs based on health risk assessments using the most current scientific methods. As defined in statute, PHGs for non-carcinogenic chemicals in drinking water are set at a concentration “at which no known or anticipated adverse health effects will occur, with an adequate margin of safety.” For carcinogens, PHGs are set at a concentration that “does not pose any significant risk to health.” PHGs provide one basis for revising MCLs, along with cost and technological feasibility.

OEHHA has been publishing PHGs since 1997 and the entire list published to date is shown in Table 1.

Table 2 presents health risk information for contaminants that do not have PHGs but have state or federal regulatory standards. The Act requires that, for chemical contaminants with California MCLs that do not yet have PHGs, water utilities use the federal Maximum Contaminant Level Goal (MCLG) for the purpose of complying with the requirement of public notification. MCLGs, like PHGs, are strictly health based and include a margin of safety. One difference, however, is that the MCLGs for carcinogens are set at zero because the US Environmental Protection Agency (US EPA) assumes there is no absolutely safe level of exposure to such chemicals. PHGs, on the other hand, are set at a level considered to pose no significant risk of cancer; this is usually no more than a one-in-one-million excess cancer risk (1×10 -6) level for a lifetime of
exposure. In Table 2, the cancer risks shown are based on the US EPA’s evaluations.

For more information on health risks: The adverse health effects for each chemical with a PHG are summarized in a PHG technical support document. These documents are available on the OEHHA website (https://oehha.ca.gov/water/public-health-goals- phgs).

Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2022 3
Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs)
Chemical Health Risk Category1
California
PHG
(mg/L)2
Cancer
Risk3
at the
PHG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
Alachlor carcinogenicity
(causes cancer)

0.004 NA5,6 0.002 NA
Aluminum neurotoxicity and
immunotoxicity
(harms the nervous and
immune systems)

0.6 NA 1 NA
Antimony hepatotoxicity
(harms the liver)

0.001 NA 0.006 NA
Arsenic carcinogenicity
(causes cancer)

0.000004
(4×10-6)
1×10-6
(one per
million)

0.01 2.5×10-3
(2.5 per
thousand)
Asbestos carcinogenicity
(causes cancer)
7 MFL7
(fibers >10
microns in
length)
1×10-6 7 MFL
(fibers >10
microns in
length)
1×10-6
(one per
million)
Atrazine carcinogenicity
(causes cancer)

0.00015 1×10-6 0.001 7×10-6
(seven per
million)

1 Based on the OEHHA PHG technical support document unless otherwise specified. The categories are the hazard traits defined by OEHHA for California’s Toxics Information Clearinghouse (online at:
https://oehha.ca.gov/media/downloads/risk-assessment//gcregtext011912.pdf). 2 mg/L = milligrams per liter of water or parts per million (ppm) 3 Cancer Risk = Upper bound estimate of excess cancer risk from lifetime exposure. Actual cancer risk may be lower or zero. 1×10-6 means one excess cancer case per million people exposed. 4 MCL = maximum contaminant level.
5 NA = not applicable. Cancer risk cannot be calculated. 6 The PHG for alachlor is based on a threshold model of carcinogenesis and is set at a level that is believed to be without any significant cancer risk to individuals exposed to the chemical over a lifetime. 7 MFL = million fibers per liter of water.

Off
ice of Environmental Health Hazard Assessment
Water Toxicology Section
February 2022 4
Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs)
Chemical Health Risk Category1
California
PHG
(mg/L)2
Cancer
Risk3
at the
PHG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
Barium cardiovascular toxicity
(causes high blood
pressure)
2 NA 1 NA
Bentazon hepatotoxicity and
digestive system toxicity
(harms the liver,
intestine, and causes
body weight effects8)

0.2 NA 0.018 NA
Benzene carcinogenicity
(causes leukemia)

0.00015 1×10-6 0.001 7×10-6
(seven per
million)
Benzo[a]pyrene carcinogenicity
(causes cancer)

0.000007
(7×10-6)
1×10-6 0.0002 3×10-5
(three per
hundred
thousand)
Beryllium digestive system toxicity
(harms the stomach or
intestine)

0.001 NA 0.004 NA
Bromate carcinogenicity
(causes cancer)

0.0001 1×10-6 0.01 1×10-4
(one per
ten
thousand)
Cadmium nephrotoxicity
(harms the kidney)

0.00004 NA 0.005 NA
Carbofuran reproductive toxicity
(harms the testis)

0.0007 NA 0.018 NA
8 Body weight effects are an indicator of general toxicity in animal studies.

Offic
e of Environmental Health Hazard Assessment
Water Toxicology Section
February 2022 5
Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs)
Chemical Health Risk Category1
California
PHG
(mg/L)2
Cancer
Risk3
at the
PHG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
Carbon
tetrachloride
carcinogenicity
(causes cancer)

0.0001 1×10-6 0.0005 5×10-6
(five per
million)
Chlordane carcinogenicity
(causes cancer)

0.00003 1×10-6 0.0001 3×10-6
(three per
million)
Chlorite hematotoxicity
(causes anemia)
neurotoxicity
(causes neurobehavioral
effects)

0.05 NA 1 NA
Chromium,
hexavalent
carcinogenicity
(causes cancer)

0.00002 1×10-6 none NA
Copper digestive system toxicity
(causes nausea,
vomiting, diarrhea)

0.3 NA 1.3 (AL9) NA
Cyanide neurotoxicity
(damages nerves)
endocrine toxicity
(affects the thyroid)

0.15 NA 0.15 NA
Dalapon nephrotoxicity
(harms the kidney)

0.79 NA 0.2 NA
Di(2-ethylhexyl)
adipate (DEHA)
developmental toxicity
(disrupts development)

0.2 NA 0.4 NA
9 AL = action level. The action levels for copper and lead refer to a concentration measured at the tap. Much of the copper and lead in drinking water is derived from household plumbing (The Lead and Copper Rule, Title 22, California Code of Regulations [CCR] section 64672.3).

Off
ice of Environmental Health Hazard Assessment
Water Toxicology Section
February 2022 6
Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs)
Chemical Health Risk Category1
California
PHG
(mg/L)2
Cancer
Risk3
at the
PHG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
Di(2-ethylhexyl)
phthalate
(DEHP)
carcinogenicity
(causes cancer)

0.012 1×10-6 0.004 3×10-7
(three per
ten million)
1,2-Dibromo-3-
chloropropane
(DBCP)
carcinogenicity
(causes cancer)

0.000003
(3x10-6)
1×10-6 0.0002 7×10-5
(seven per
hundred
thousand)
1,2-Dichloro-
benzene
(o-DCB)
hepatotoxicity
(harms the liver)

0.6 NA 0.6 NA
1,4-Dichloro-
benzene
(p-DCB)
carcinogenicity
(causes cancer)

0.006 1×10-6 0.005 8×10-7
(eight per
ten million)
1,1-Dichloro-
ethane
(1,1-DCA)
carcinogenicity
(causes cancer)

0.003 1×10-6 0.005 2×10-6
(two per
million)
1,2-Dichloro-
ethane
(1,2-DCA)
carcinogenicity
(causes cancer)

0.0004 1×10-6 0.0005 1×10-6
(one per
million)
1,1-Dichloro-
ethylene
(1,1-DCE)
hepatotoxicity
(harms the liver)

0.01 NA 0.006 NA
1,2-Dichloro-
ethylene, cis
nephrotoxicity
(harms the kidney)

0.013 NA 0.006 NA
1,2-Dichloro-
ethylene, trans
immunotoxicity
(harms the immune
system)

0.05 NA 0.01 NA

Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2022 7
Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs)
Chemical Health Risk Category1
California
PHG
(mg/L)2
Cancer
Risk3
at the
PHG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
Dichloromethane
(methylene
chloride)
carcinogenicity
(causes cancer)

0.004 1×10-6 0.005 1×10-6
(one per
million)
2,4-Dichloro-
phenoxyacetic
acid (2,4-D)
hepatotoxicity and
nephrotoxicity
(harms the liver and
kidney)

0.02 NA 0.07 NA
1,2-Dichloro-
propane
(propylene
dichloride)
carcinogenicity
(causes cancer)

0.0005 1×10-6 0.005 1×10-5
(one per
hundred
thousand)
1,3-Dichloro-
propene
(Telone II)
carcinogenicity
(causes cancer)

0.0002 1×10-6 0.0005 2×10-6
(two per
million)
Dinoseb reproductive toxicity
(harms the uterus and
testis)

0.014 NA 0.007 NA
Diquat ocular toxicity
(harms the eye)
developmental toxicity
(causes malformation)

0.006 NA 0.02 NA
Endothall digestive system toxicity
(harms the stomach or
intestine)

0.094 NA 0.1 NA
Endrin neurotoxicity
(causes convulsions)
hepatotoxicity
(harms the liver)

0.0003 NA 0.002 NA
Ethylbenzene
(phenylethane)
hepatotoxicity
(harms the liver)

0.3 NA 0.3 NA
Offic
e of Environmental Health Hazard Assessment
Water Toxicology Section
February 2022 8
Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs)
Chemical Health Risk Category1
California
PHG
(mg/L)2
Cancer
Risk3
at the
PHG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
Ethylene
dibromide (1,2-
Dibromoethane)
carcinogenicity
(causes cancer)

0.00001 1×10-6 0.00005 5×10-6
(five per
million)
Fluoride musculoskeletal toxicity
(causes tooth mottling)
1 NA 2 NA
Glyphosate nephrotoxicity
(harms the kidney)

0.9 NA 0.7 NA
Heptachlor carcinogenicity
(causes cancer)

0.000008
(8×10-6)
1×10-6 0.00001 1×10-6
(one per
million)
Heptachlor
epoxide
carcinogenicity
(causes cancer)

0.000006
(6×10-6)
1×10-6 0.00001 2×10-6
(two per
million)
Hexachloroben-
zene
carcinogenicity
(causes cancer)

0.00003 1×10-6 0.001 3×10-5
(three per
hundred
thousand)
Hexachloro-
cyclopentadiene
(HCCPD)
digestive system toxicity
(causes stomach
lesions)

0.002 NA 0.05 NA
Lead developmental
neurotoxicity
(causes neurobehavioral
effects in children)
cardiovascular toxicity
(causes high blood
pressure)
carcinogenicity
(causes cancer)

0.0002 <1×10-6
(PHG is
not based
on this
effect)

0.015
(AL9)
2×10-6
(two per
million)

Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2022 9
Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs)
Chemical Health Risk Category1
California
PHG
(mg/L)2
Cancer
Risk3
at the
PHG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
Lindane
(γ-BHC)
carcinogenicity
(causes cancer)

0.000032 1×10-6 0.0002 6×10-6
(six per
million)
Mercury
(inorganic)
nephrotoxicity
(harms the kidney)

0.0012 NA 0.002 NA
Methoxychlor endocrine toxicity
(causes hormone
effects)

0.00009 NA 0.03 NA
Methyl tertiary-
butyl ether
(MTBE)
carcinogenicity
(causes cancer)

0.013 1×10-6 0.013 1×10-6
(one per
million)
Molinate carcinogenicity
(causes cancer)

0.001 1×10-6 0.02 2×10-5
(two per
hundred
thousand)
Monochloro-
benzene
(chlorobenzene)
nephrotoxicity
(harms the kidney)

0.07 NA 0.07 NA
Nickel developmental toxicity
(causes increased
neonatal deaths)

0.012 NA 0.1 NA
Nitrate hematotoxicity
(causes
methemoglobinemia)
45 as
nitrate
NA 10 as
nitrogen
(=45 as
nitrate)
NA
Nitrite hematotoxicity
(causes
methemoglobinemia)
3 as
nitrite
NA 1 as
nitrogen
(=3 as
nitrite)
NA
Offic
e of Environmental Health Hazard Assessment
Water Toxicology Section
February 2022 10
Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs)
Chemical Health Risk Category1
California
PHG
(mg/L)2
Cancer
Risk3
at the
PHG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
Nitrate and
Nitrite
hematotoxicity
(causes
methemoglobinemia)
10 as
nitrogen10
NA 10 as
nitrogen
NA
N-nitroso-
dimethyl-amine
(NDMA)
carcinogenicity
(causes cancer)

0.000003
(3×10-6)
1×10-6 none NA
Oxamyl general toxicity
(causes body weight
effects)

0.026 NA 0.05 NA
Pentachloro-
phenol (PCP)
carcinogenicity
(causes cancer)

0.0003 1×10-6 0.001 3×10-6
(three per
million)
Perchlorate endocrine toxicity
(affects the thyroid)
developmental toxicity
(causes neurodevelop-
mental deficits)

0.001 NA 0.006 NA
Picloram hepatotoxicity
(harms the liver)

0.166 NA 0.5 NA
Polychlorinated
biphenyls
(PCBs)
carcinogenicity
(causes cancer)

0.00009 1×10-6 0.0005 6×10-6
(six per
million)
Radium-226 carcinogenicity
(causes cancer)

0.05 pCi/L 1×10-6 5 pCi/L
(combined
Ra226+228)
1×10-4
(one per
ten
thousand)
10 The joint nitrate/nitrite PHG of 10 mg/L (10 ppm, expressed as nitrogen) does not replace the individual values, and the maximum contribution from nitrite should not exceed 1 mg/L nitrite-nitrogen.

Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2022 11
Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs)
Chemical Health Risk Category1
California
PHG
(mg/L)2
Cancer
Risk3
at the
PHG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
Radium-228 carcinogenicity
(causes cancer)

0.019 pCi/L 1×10-6 5 pCi/L
(combined
Ra226+228)
3×10-4
(three per
ten
thousand)
Selenium integumentary toxicity
(causes hair loss and
nail damage)

0.03 NA 0.05 NA
Silvex (2,4,5-TP) hepatotoxicity
(harms the liver)

0.003 NA 0.05 NA
Simazine general toxicity
(causes body weight
effects)

0.004 NA 0.004 NA
Strontium-90 carcinogenicity
(causes cancer)

0.35 pCi/L 1×10-6 8 pCi/L 2×10-5
(two per
hundred
thousand)
Styrene
(vinylbenzene)
carcinogenicity
(causes cancer)

0.0005 1×10-6 0.1 2×10-4
(two per
ten
thousand)
1,1,2,2-
Tetrachloro-
ethane
carcinogenicity
(causes cancer)

0.0001 1×10-6 0.001 1×10-5
(one per
hundred
thousand)
2,3,7,8-Tetra-
chlorodibenzo-p-
dioxin (TCDD, or
dioxin)
carcinogenicity
(causes cancer)

5×10-11 1×10-6 3×10-8 6×10-4
(six per ten
thousand)
Off
ice of Environmental Health Hazard Assessment
Water Toxicology Section
February 2022 12
Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs)
Chemical Health Risk Category1
California
PHG
(mg/L)2
Cancer
Risk3
at the
PHG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
Tetrachloro-
ethylene
(perchloro-
ethylene, or
PCE)
carcinogenicity
(causes cancer)

0.00006 1×10-6 0.005 8×10-5
(eight per
hundred
thousand)
Thallium integumentary toxicity
(causes hair loss)

0.0001 NA 0.002 NA
Thiobencarb general toxicity
(causes body weight
effects)
hematotoxicity
(affects red blood cells)

0.042 NA 0.07 NA
Toluene
(methylbenzene)
hepatotoxicity
(harms the liver)
endocrine toxicity
(harms the thymus)

0.15 NA 0.15 NA
Toxaphene carcinogenicity
(causes cancer)

0.00003 1×10-6 0.003 1×10-4
(one per
ten
thousand)
1,2,4-Trichloro-
benzene
endocri
ne toxicity
(harms adrenal glands)

0.005 NA 0.005 NA
1,1,1-Trichloro-
ethane
neurotoxicity
(harms the nervous
system),
reproductive toxicity
(causes fewer offspring)
hepatotoxicity
(harms the liver)
hematotoxicity
(causes blood effects)
1 NA 0.2 NA

Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2022 13
Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs)
Chemical Health Risk Category1
California
PHG
(mg/L)2
Cancer
Risk3
at the
PHG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
1,1,2-Trichloro-
ethane
carcinogenicity
(causes cancer)

0.0003 1x10-6 0.005 2×10-5
(two per
hundred
thousand)
Trichloro-
ethylene (TCE)
carcinogenicity
(causes cancer)

0.0017 1×10-6 0.005 3×10-6
(three per
million)
Trichlorofluoro-
methane
(Freon 11)
accelerated mortality
(increase in early death)

1.3 NA 0.15 NA
1,2,3-Trichloro-
propane
(1,2,3-TCP)
carcinogenicity
(causes cancer)

0.0000007
(7×10-7)
1x10-6 0.000005
(5×10-6)
7×10-6
(seven per
million)
1,1,2-Trichloro-
1,2,2-trifluoro-
ethane
(Freon 113)
hepatotoxicity
(harms the liver)
4 NA 1.2 NA
Trihalomethanes:

Bromodichloro-
methane
carcinogenicity
(causes cancer)

0.00006 1x10-6 0.080* 1.3×10-3
(1.3 per
thousand)11
Trihalomethanes:

Bromoform
carcinogenicity
(causes cancer)

0.0005 1x10-6 0.080* 2×10-4
(two per ten
thousand)12

* For total trihalomethanes (the sum of bromodichloromethane, bromoform, chloroform, and dibromochloromethane). There are no MCLs for individual trihalomethanes. 11 Based on 0.080 mg/L bromodichloromethane; the risk will vary with different combinations and ratios of the other trihalomethanes in a particular sample.
12 Based on 0.080 mg/L bromoform; the risk will vary with different combinations and ratios of the other trihalomethanes in a particular sample.

Off
ice of Environmental Health Hazard Assessment
Water Toxicology Section
February 2022 14
Table 1: Health Risk Categories and Cancer Risk Values for Chemicals with California Public Health Goals (PHGs)
Chemical Health Risk Category1
California
PHG
(mg/L)2
Cancer
Risk3
at the
PHG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
Trihalomethanes:

Chloroform
carcinogenicity
(causes cancer)

0.0004 1x10-6 0.080* 2×10-4
(two per ten
thousand)13
Trihalomethanes:

Dibromochloro-
methane
carcinogenicity
(causes cancer)

0.0001 1x10-6 0.080* 8×10-4
(eight
per ten
thousand)14
Tritium carcinogenicity
(causes cancer)
400 pCi/L 1x10-6 20,000
pCi/L
5×10-5
(five per
hundred
thousand)
Uranium carcinogenicity
(causes cancer)

0.43 pCi/L 1×10-6 20 pCi/L 5×10-5
(five per
hundred
thousand)
Vinyl chloride carcinogenicity
(causes cancer)

0.00005 1×10-6 0.0005 1×10-5
(one per
hundred
thousand)
Xylene neurotoxicity
(affects the senses,
mood, and motor
control)

1.8 (single
isomer or
sum of
isomers)
NA 1.75 (single
isomer or
sum of
isomers)
NA
* For total trihalomethanes (the sum of bromodichloromethane, bromoform, chloroform, and dibromochloromethane). There are no MCLs for individual trihalomethanes. 13 Based on 0.080 mg/L chloroform; the risk will vary with different combinations and ratios of the other trihalomethanes in a particular sample.
14 Based on 0.080 mg/L dibromochloromethane; the risk will vary with different combinations and ratios of the other trihalomethanes in a particular sample.

Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2022 15
Table 2: Health Risk Categories and Cancer Risk Values for Chemicals without California Public Health Goals
Chemical Health Risk Category1

US EPA
MCLG2
(mg/L)
Cancer
Risk3
at the
MCLG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
Disinfection byproducts (DBPs)
Chloramines acute toxicity
(causes irritation)
digestive system toxicity
(harms the stomach)
hematotoxicity
(causes anemia)
45,6 NA7 none NA
Chlorine acute toxicity
(causes irritation)
digestive system toxicity
(harms the stomach)
45,6 NA none NA
Chlorine dioxide hematotoxicity
(causes anemia)
neurotoxicity
(harms the nervous
system)

0.85,6 NA none NA
Disinfection byproducts: haloacetic acids (HAA5)
Monochloroacetic
acid (MCA)
general toxicity
(causes body and organ
weight changes
8)

0.07 NA none NA

1 Health risk category based on the US EPA MCLG document or California MCL document unless otherwise specified.
2 MCLG = maximum contaminant level goal established by US EPA. 3 Cancer Risk = Upper estimate of excess cancer risk from lifetime exposure. Actual cancer risk may be lower or zero. 1×10-6 means one excess cancer case per million people exposed. 4 California MCL = maximum contaminant level established by California. 5 Maximum Residual Disinfectant Level Goal, or MRDLG.
6 The federal Maximum Residual Disinfectant Level (MRDL), or highest level of disinfectant allowed in drinking water, is the same value for this chemical. 7 NA = not available.
8 Body weight effects are an indicator of general toxicity in animal studies.

Off
ice of Environmental Health Hazard Assessment
Water Toxicology Section
February 2022 16
Table 2: Health Risk Categories and Cancer Risk Values for Chemicals without California Public Health Goals
Chemical Health Risk Category1
US EPA
MCLG2
(mg/L)
Cancer
Risk3
at the
MCLG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
Dichloroacetic
acid (DCA)
Carcinogenicity
(causes cancer)
0 0 none NA
Trichloroacetic
acid (TCA)
hepatotoxicity
(harms the liver)

0.02 NA none NA
Monobromoacetic
acid (MBA)
NA none NA none NA
Dibromoacetic
acid (DBA)
NA none NA none NA
Total haloacetic
acids (sum of

MCA, DCA, TCA,
MBA, and DBA)
general toxicity,
hepatotoxicity and
carcinogenicity
(causes body and organ
weight changes, harms
the liver and causes
cancer)
none NA 0.06 NA
Radionuclides
Gross alpha
particles9
carcinogenicity
(causes cancer)
0 (210Po
included)
0 15 pCi/L10
(includes
radium but
not radon
and
uranium)
up to 1x10-3
(for 210Po,
the most
potent alpha
emitter)
9 MCLs for gross alpha and beta particles are screening standards for a group of radionuclides.

Corresponding PHGs were not developed for gross alpha and beta particles. See the OEHHA memoranda discussing the cancer risks at these MCLs at
http://www.oehha.ca.gov/water/reports/grossab.html
.
10 pCi/L = picocuries per liter of water.

Offi
ce of Environmental Health Hazard Assessment
Water Toxicology Section
February 2022 17
Table 2: Health Risk Categories and Cancer Risk Values for Chemicals without California Public Health Goals
Chemical Health Risk Category1
US EPA
MCLG2
(mg/L)
Cancer
Risk3
at the
MCLG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
Beta particles
and photon
emitters
9 carcinogenicity
(causes cancer)
0 (210Pb
included)
0 50 pCi/L
(judged
equiv. to 4
mrem/yr)
up to 2x10-3
(for 210Pb,
the most
potent beta-
emitter)
2022 Public Health Goals Report San Francisco Water System

Attachmen
t C
SFWS Water Quality Reports - 2019, 2020, 2021
P.O. Box 7369
San Francisco, CA 94120-7369
@sfwater
This report contains important information about your drinking water. Translate it, or speak with someone who understands it.

Este informe contiene información muy importante sobre su agua potable. Tradúzcalo o hable con alguien que lo entienda bien.

Mahalaga ang impormasyong ito. Mangyaring ipasalin ito.

Cé rapport contient des information importantes concernant votre eau potable. Veuillez traduire, ou parlez avec quelqu’ un qui peut le comprendre.

Dieser Bericht enthält wichtige Information über Ihr Trinkwasser. Bitte übersetzen Sie ihn oder sprechen Sie mit jemandem, der ihn versteht.

Questo rapporto contiene informazioni importanti che riguardano la vostra aqua potabile.

Traducetelo, o parlate con una persona qualiﬁ cata in grado di spiegarvelo. 㘤ɻ ੥ፙଞਓҝ㟬຋ᩄ࿨ղ㘸ਗ਼ુɻ
Этот отчет содержит важную информацию о вашей питьевой воды. Переведите его или поговорите с тем, кто это понимает.
この報告書には上水道に関する重要な情報が記されております。翻訳を御依頼なされ
るか、内容をご理解なさっておられる方にお尋ね下さい。
Ann Moller Caen, PRESIDENT
Francesca Vietor, VICE PRESIDENT
Anson Moran, COMMISSIONER
Sophie Maxwell, COMMISSIONER
Tim Paulson, COMMISSIONER
San Francisco Public Utilities Commission
Every day we deliver high-quality drinking water to 2.7 million people in San Francisco, Alameda, Santa Clara and San Mateo counties. We generate clean, reliable hydroelectricity that powers 100% of San Francisco’s vital services, including police and ﬁ re stations, street lights, Muni, SF General Hospital and more.

This report contains important information about our
drinking water. Please contact SFPUC Communications at
415-554-3289 or email [email protected] for assistance.

Este informe contiene información muy importante sobre
su agua para beber. Favor de comunicarse SFPUC a
415-554-3289 para asistirlo en español.

The San Francisco Public
Utilities Commission
meets on the 2nd and 4th
Tuesday of every month.

To ﬁ nd out more about
our Commissioners and
past meetings, visit
sfwater.org/commission

CITY OF SAN FRANCISCO
2019 ANNUAL
WATER

QUALITY
REPORT

UNDERSTANDING THIS REPORT
The San Francisco Public Utilities Commission (SFPUC) produces this annual report detailing where your water comes from, how we treat it, and its overall chemical composition. We do this as a regulatory requirement, and we think it is important for you to understand the information within it.

We are committed to providing high quality drinking water for all our customers. Our system is large and we work across several counties to maintain the system that delivers our water. In addition to the wider system outside of San Francisco, we also maintain a system of reservoirs within San Francisco. It is our hope that this report will not only provide you with greater knowledge of your water, but also an increased understanding of the considerable skill, talent, and effort that goes into ensuring businesses and residents have reliable access to this precious resource.

We’re proud of our water, and we hope you are too. Throughout this report, you’ll ﬁ nd facts and ﬁ gures to help expand upon the basic information we’re required to provide. We hope you enjoy getting to know a little more about who we are as an Agency and how you can get involved.

WATER FACT:

The SFPUC is the third
largest utility in the State
of California, serving

2.7 million residential,
commercial and industrial
customers in the Bay Area,
and we operate 24/7 –
365 days every year
FOOTNOTES ON SAN FRANCISCO WATER SYSTEM - WATER QUALITY DATA:
(1) These are monthly average turbidity values measured every 4 hours daily. (2) There is no turbidity MCL for ﬁ ltered water. The limits are based on the TT requirements for ﬁ ltration systems. (3) This is the highest locational running annual average value. (4) Total organic carbon is a precursor for disinfection byproduct formation. The TT requirement applies to the ﬁ ltered water from the SVWTP only. (5) In May 2015, the SWRCB-DDW recommended an optimal ﬂ uoride level of 0.7 ppm be maintained in the treated water. In 2019, the range and average of the ﬂ uoride levels were 0.2 ppm - 0.9 ppm and 0.7 ppm, respectively. (6) The natural ﬂ uoride level in the Hetch Hetchy source was ND. Elevated ﬂ uoride levels in the raw water at SVWTP and HTWTP were attributed to the transfer of ﬂ uoridated Hetch Hetchy water into the local reservoirs. (7) This is the highest running annual average value. (8) Alumin um also has a primary MCL of 1,000 ppb. (9) The most recent Lead and Copper Rule monitoring was in August 2018. Two of the 90 site samples collected at consumer taps had lead concentrations above the AL. (10) The detected chlorate in the treated water is a degradation product of sodium hypochlorite, which we use for water disinfection. (11) Chromium (VI) has a PHG of 0.02 ppb but no MCL. The previous MCL of 10 ppb was withdrawn by the SWRCB-DDW on September 11, 2017. Currently, the SWRCB-DDW regulates all chromium through a MCL of 50 ppb for Total Chromium, which was not detected in our water in 2019.

Note: The different water sources blended at different ratios throughout the year have resulted in varying water quality. Additional water quality data may be obtained by calling our Water Quality Division toll-free number at (877) 737-8297.

Treated Water
(Sunset
Reservoir)

DETECTED CONTAMINANTS UNIT MCL PHG RANGE

FOUND AVERAGE MAJOR SOURCES IN DRINKING WATER

INORGANICS
Chromium (VI) ppb N/A (1) 0.02 0.08 - 0.91 0.24 Leaching from natural deposits; commercial and industrial waste discharges, e.g., electroplating.

CONSTITUENTS WITH SECONDARY STANDARDS
Chloride ppb 500 N/A 4.8 4.8 Runoff / leaching from natural deposits Color Unit 15 N/A 8 8 Naturally-occurring organic materials Speciﬁ c Conductance μS/cm 1600 N/A 61 - 397 125 Substances that form ions when in water Sulfate Unit 500 N/A 5.5 5.5 Runoff / leaching from natural deposits Total Dissolved Solids ppm 1000 N/A 33 33 Runoff / leaching from natural deposits Turbidity NTU 5 N/A 0.3 0.3 Soil runoff

OTHER WATER QUALITY

PARAMETERS

UNIT ORL RANGE
FOUND

AVERAGE
Chlorate (2) ppb 800 (NL) 61 61
Strontium ppb N/A 49 49
Raw Water (3)
(San Francisco
Local
Groundwater
Wells)

DETECTED CONTAMINANTS UNIT MCL PHG RANGE

FOUND AVERAGE MAJOR SOURCES IN DRINKING WATER

INORGANICS
Chromium (VI) ppb N/A(1) 0.02 0.02 - 23.7 15.9 Leaching from natural deposits; commercial and industrial waste discharges, e.g., electroplating.

Nitrate (as nitrogen) ppm 10 10 3 - 13.6 8.0 Landscape fertilizers and leaked wastewater.

VOLATILE ORGANICS
Carbon tetrachloride (4) ppb 0.5 0.1 ND - 0.99 0.61 (4) Commercial and industrial solvent used in dry cleaning prior to 1960.

Tetrachloroethylene (5) ppb 5 0.06 ND - 2.5 1.9 (5) Commercial and industrial solvent used in dry cleaning prior to 2010, and as a metal degreaser in
auto shops and metalworking industries.

OTHER WATER QUALITY

PARAMETERS UNIT ORL
RANGE

FOUND AVERAGE
pH - N/A 7.3 - 8.5 7.9
Strontium ppb N/A 134 - 202 176
FOOTNOTES ON SAN FRANCISCO LOCAL GROUNDWATER - WATER QUALITY DATA:
(1) The previous Chromium (VI) MCL of 10 ppb was withdrawn by the SWRCB-DDW on September 11, 2017. Currently, the SWRCB-DDW regulates total chromium through a MCL of 50 ppb. The results of total chromium in treated water was ND in 2019. (2) The detected chlorate in the treated water is a degradation product of sodium hypochlorite, which is used fo r water disinfection and maintenance of chlorine residual in the system. (3) The concentration ranges and averages of these co ntaminants are indicative of the raw groundwater quality prior to treatment. They are not representative of water in the reservoirs and distribution system. (4) This contaminant was detected above the MCL at South Sunset Well only. The average is based on the monitoring results from South Sunset Well. (5) This contaminant was detected only at Golden Gate Central Well, which is currently se rving Golden Gate Park of irrigation purpose only. The average is based on the monitoring results from Golden Gate Central Well.

San Francisco Local Groundwater - Water Quality Data for Year 2019 SAN FRANCISCO WATER SYSTEM-WATER QUALITY DATA FOR 2019
The table below lists all 2019 detected drinking water contaminants and the information about their typical sources.

Contaminants below detection limits for reporting are not shown, in accord with regulatory guidance. We hold a SWRCB-DDW monitoring waiver for some contaminants in our surface water supply and therefore their monitoring frequencies are less than annual. Visit sfwater.org for a list of all water quality parameters we monitored in raw water and treated water in 2019.

DETECTED CONTAMINANTS UNIT MCL PHG

OR (MCLG)

RANGE OR

LEVEL FOUND

AVERAGE
OR [MAX] MAJOR SOURCES IN DRINKING WATER

TURBIDITY
Unﬁ ltered Hetch Hetchy Water NTU 5 N/A 0.3 - 0.7 (1) [2.1] Soil runoff Filtered Water from Sunol Valley
Water Treatment Plant (SVWTP)
NTU
-
1 (2)
Min 95% of
samples
≤0.3 NTU (2)
N/A
N/A
-

99.9% - 100%
[1]
-
Soil runoff
Soil runoff
Filtered Water from Harry Tracy
Water Treatment Plant (HTWTP)
NTU
-
1 (2)
Min 95% of
samples
≤0.3 NTU (2)
N/A
N/A
-
100%
[0.1]
-
Soil runoff
Soil runoff

DISINFECTION BY-PRODUCTS AND PRECURSOR
Total Trihalomethanes ppb 80 N/A 13 - 65 [45] (3) By-product of drinking water disinfection Haloacetic Acids ppb 60 N/A 7.2 - 46 [38] (3) By-product of drinking water disinfection Total Organic Carbon (4) ppm TT N/A 1.6 - 2.6 2.1 Various natural and man-made sources

MICROBIOLOGICAL
Total Coliform - NoP ≤5.0% of
monthly samples (0) - [0.3%] Naturally present in the environment Giardia lamblia cyst/L TT (0) 0 - 0.09 0.02 Naturally present in the environment

INORGANICS
Fluoride (source water) (5) ppm 2.0 1 ND - 0.9 0.3 (6) Erosion of natural deposits; water additive to promote strong teeth Chloramine (as chlorine) ppm MRDL = 4.0 MRDLG = 4 0.5 - 3.3 [2.6] (7) Drinking water disinfectant added for treatment

CONSTITUENTS WITH

SECONDARY STANDARDS UNIT SMCL PHG RANGE AVERAGE MAJOR SOURCES OF CONTAMINANT Aluminum (8) ppb 200 600 ND - 68 ND Erosion of natural deposits; some surface water treatment residue
Chloride ppm 500 N/A <3 - 17 8.7 Runoff / leaching from natural deposits Color unit 15 N/A <5 - 10 <5 Naturally-occurring organic materials Speciﬁ c Conductance μS/cm 1600 N/A 32 - 234 158 Substances that form ions when in water Sulfate ppm 500 N/A 1 - 29 15 Runoff / leaching from natural deposits Total Dissolved Solids ppm 1000 N/A <20 - 119 76 Runoff / leaching from natural deposits Turbidity NTU 5 N/A ND - 0.5 0.2 Soil runoff
LEAD AND COPPER (9) UNIT AL PHG RANGE 90TH

PERCENTILE MAJOR SOURCES IN DRINKING WATER
Copper ppb 1300 300 7.7 - 103 64 Internal corrosion of household water plumbing systems Lead ppb 15 0.2 <1 - 90 6 Internal corrosion of household water plumbing systems

OTHER WATER QUALITY

PARAMETERS

UNIT ORL RANGE AVERAGE KEY
Alkalinity (as CaCO3) ppm N/A 3.5 - 97 46 < / ≤ = less than / less than or equal t o AL = A ction Level
Max = M aximum
Min = Minimum
N/A = Not Available
ND = Non-Detect
NL = N otiﬁ cation Level
NoP = Number of Coliform-Positive Sample
NTU = Nephelometric Turbidity Unit
ORL = Other Re gulatory Level
ppb = part per billion
ppm = part per million
μS/cm = microSiemens/centimete r
Boron ppb 1000 (NL) ND - 107 ND
Calcium (as Ca) ppm N/A 3.3 - 20 12
Chlorate (10) ppb 800 (NL) 40 - 220 84
Chromium (VI) (11) ppb NA 0.04 - 0.19 0.12
Hardness (as CaCO3) ppm N/A 8.9 - 77 47
Magnesium ppm N/A 0.2 - 6.6 4.2
pH - N/A 8.6 - 9.9 9.4
Potassium ppm N/A 0.3 - 1.2 0.8
Silica ppm N/A 4.9 - 8 6.1
Sodium ppm N/A 2.8 - 21 14
Strontium ppb N/A 13 - 230 107
We conduct watershed sanitary surveys for the Hetch Hetchy source annually, for the local water, and Upcountry Non- Hetch Hetchy Sources (UNHHS) every ﬁ ve years. The latest local sanitary survey was completed in 2016 for the period of 2011 - 2015. The last watershed sanitary survey for UNHHS was conducted in 2015 as part of our drought response plan efforts. All these surveys together with our stringent watershed protection activities were completed with support from partner agencies including the National Park Service and the US Forest Service. The purpose of these surveys is to evaluate the sanitary conditions and water quality of the watersheds and to review results of watershed management activities conducted in the preceding years. Wildlife, stock, and human activities continue to be potential contamination sources.

You may contact the San Francisco District ofﬁ ce of the State Water Resources Control Board’s Division of Drinking Water (SWRCB-DDW) at 510-620-3474 to review these reports.

WATER FACT:

Groundwater is widely used
across California and throughout
the world. While it is true not all
groundwater sources (aquifers)
are the same, we’re proud
of ours. To learn more about
the Westside Basin and our
groundwater, please visit
sfwater.org/groundwater

OUR DRINKING WATER

SOURCES AND TREATMENT

PROTECTING

OUR WATERSHEDS
Our drinking water comes from a variety of protected sources carefully managed by the SFPUC. These sources include surface water stored in reservoirs located in the Sierra Nevada, Alameda County and San Mateo County, and groundwater supplies stored in a deep aquifer located in San Francisco and San Mateo counties. These sources are diverse in both the origin of the supply – snowmelt, rainfall and recharge of groundwater – and their location within our system.

Maintaining this variety of sources is an important component of our near and long-term water supply management strategy. A diverse mix of sources protects us from potential disruptions due to emergencies or natural disasters, provides resiliency during periods of drought, and helps us ensure a long-term, sustainable water supply as we address issues such as climate uncertainty, regulatory changes and population growth.

To meet drinking water standards for consumption, water from all of our surface water sources undergoes treatment before it is delivered to our customers.

Water from the Hetch Hetchy Reservoir is exempt from state and federal ﬁ ltration requirements but receives the following treatment: ultraviolet light and chlorine disinfection, pH adjustment for optimum corrosion control, ﬂ uoridation for dental health protection, and chloramination for maintaining disinfectant residual and minimizing the formation of regulated disinfection byproducts. Water from local Bay Area reservoirs in Alameda County and San Mateo County is delivered to Sunol Valley Water Treatment Plant (SVWTP) and Harry Tracy Water Treatment Plant (HTWTP), respectively, and is treated by ﬁ ltration, disinfection, ﬂ uoridation, optimum corrosion control and taste and odor removal processes.

Mandated by State law, water ﬂ uoridation is a widely accepted practice proven to be safe and effective for preventing and controlling tooth decay.

Our ﬂ uoride target level in the water is 0.7 milligram per liter (mg/L, or part per million, ppm), consistent with the May 2015 State regulatory guidance on optimal ﬂ uoride level. Infants fed formula mixed with water containing ﬂ uoride at this level may still have a chance of developing tiny white lines or streaks in their teeth. These marks are referred to as mild to very mild ﬂ uorosis, and are often only visible under a microscope. Even in cases where the marks are visible, they do not pose any health risk. The Centers for Disease Control (CDC) considers it safe to use optimally ﬂ uoridated water for preparing infant formula. To lessen this chance of dental ﬂ uorosis, you may choose to use low-ﬂ uoride bottled water to prepare infant formula.

Nevertheless, children may still develop dental ﬂ uorosis due to ﬂ uoride intake from other sources such as food, toothpaste and dental products.

Contact your healthcare provider or SWRCB-DDW if you have concerns about dental ﬂ uorosis. For additional information about ﬂ uoridation or oral health, visit the SWRCB-DDW website waterboards.ca.gov/drinking_ water/certlic/drinkingwater/Fluoridation.shtml, the CDC website cdc.gov/ﬂ uoridation, or our website sfwater.org/ﬂ uoride.

FLUORIDATION AND

DENTAL FLUOROSIS

WATER QUALITY
We regularly collect and test water samples from
reservoirs and designated sampling points throughout
the system to ensure the water delivered to you meets
or exceeds federal and state drinking water standards.

In 2019, we conducted more than 100,000 drinking
water tests in the source, transmission, and distribution system. This is in addition to the extensive treatment
process control monitoring performed by our certiﬁ ed
operators and online instruments.

Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some
contaminants. The presence of contaminants does not
necessarily indicate that water poses a health risk. In order to ensure that tap water is safe to drink, the
United States Environmental Protection Agency (USEPA)
and the SWRCB-DDW prescribe regulations that limit
the amounts of certain contaminants in water provided
by public water systems. The U.S. Food and Drug
Administration regulations and California law also
establish limits for contaminants in bottled water that provide the same protection for public health.

WATER FACT:

We’re immensely proud of
our water quality, and the
team of experts that make
it possible. It is estimated
that 785 million people in
the world are living without
access to safe water.

Source: WHO ‘Progress on
Drinking Water, Sanitation
and Hygiene,’ 2017.

WE
SF WATER.

DRINK TAP!
Your tap water is the most
sustainable choice when it
comes to drinking water sources.

Bottled water is many times more
expensive than the water from
your tap, and the carbon footprint
associated with it is avoidable.

Show your love for our water
and our planet and drink tap!

KEY WATER QUALITY TERMS
The following are deﬁ nitions of key terms referring to standards and goals of water quality noted on the data table.

Public Health Goal (PHG): The level of a contaminant in drinking water below which there is no known or expected risk to health. PHGs are set by the California Environmental Protection Agency.

Maximum Contaminant Level Goal (MCLG) : The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs are set by the USEPA.

Maximum Contaminant Level (MCL): The highest level of a contaminant that is allowed in drinking water. Primary MCLs are set as close to the PHGs or MCLGs as is economically and technologically feasible. Secondary MCLs (SMCLs) are set to protect the odor, taste, and appearance of drinking water.

Maximum Residual Disinfectant Level (MRDL) : The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.

Maximum Residual Disinfectant Level Goal (MRDLG) : The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGs do not reﬂ ect the beneﬁ ts of the use of disinfectants to control microbial contaminants.

Primary Drinking Water Standard (PDWS) : MCLs and MRDLs for contaminants that affect health along with their monitoring and reporting requirements, and water treatment requirements.

Regulatory Action Level : The concentration of a contaminant which, if exceeded, triggers treatment or other requirements that a water system must follow.

Treatment Technique (TT): A required process intended to reduce the level of a contaminant in drinking water.

Turbidity: A water clarity indicator that measures cloudiness of the water, and is also used to indicate the effectiveness of the ﬁ ltration system. High turbidity can hinder the effectiveness of disinfectants.

Cryptosporidium is a parasitic microbe found in most surface water. We regularly test for this waterborne pathogen and found it at very low levels in source water and treated water in 2019. However, current test methods approved by the USEPA do not distinguish between dead organisms and those capable of causing disease. Ingestion of Cryptosporidium may produce symptoms of nausea, abdominal cramps, diarrhea, and associated headaches.

Cryptosporidium must be ingested to cause disease, and it may be spread through means other than drinking water.

OUR WATER IN THE COMMUNITY
Throughout the spring of 2019, SFPUC staff members worked alongside local business owners to encourage appreciation for our water through a series of open house-style events.

We were lucky enough to collaborate with popular bakeries, breweries, and coffee shops across the city. These events allowed many San Francisco residents to meet staff from many different parts of our organization and learn more about our water, how it is treated, as well as some of our wonderful conservation programs and initiatives.

Later in the autumn we were fortunate enough to have some of these business partners from the spring volunteer to be featured in a visual campaign now on display in our headquarters on Golden Gate Avenue.

We were so pleased to see the enthusiasm we have for our high quality water reﬂ ected in the conversations we had with many of you. Our water makes many popular products and businesses possible, and we’re grateful for your ongoing interest in our work.

In addition to our water source protection efforts, we continue the following programs to minimize customer exposure to lead in water:
• Replacing the remaining 2% of brass meters with
lead-free automated water meters.
• Annual monitoring in our water transmission system entry points in 2019 continues to return results of non-detect. • Offering in partnership with the San Francisco Department of Public Health free lead test vouchers for clients enrolled in the Women, Infants and Children (WIC) program.
• Offering low-cost water tests for lead for $25 per tap.

To request a test, call 311 or visit our website
sfwater.org/leadtest for an application form.

In 2019, we continued inspecting and characterizing the 10,912 service lines of unknown material and 4,524 service lines suspected of having lead components, also known as lead user service lines (LUSLs). These ﬁ gures were ﬁ rst reported to SWRCB- DDW in July 2018. Results of ﬁ eld investigations, as well as a schedule to replace known LUSLs, will be reported to the SWRCB- DDW by July 2020. Our policy is to remove and replace any LUSL promptly if it is discovered during pipeline repair and/or maintenance. We are also conducting a pilot study to determine the effects of the lead components on lead levels at customer taps.

Between 2017 and 2019, we assisted a total of 190 public and private K-12 schools in lead monitoring for their tap water.

School monitoring data can be found at sfwater.org/lead.

Starting in late 2019, we have been working with San Francisco Uniﬁ ed School District to develop a voluntary, 5-year recurring monitoring program to provide continued support to local schools in addressing lead in their tap water.

LEAD TESTING

OF DRINKING

WATER IN SCHOOLS
WATER FACT:

Do you know how much water
you should have stored as part
of your emergency kit? To ﬁ nd
out visit sf72.org/supplies
The system that delivers our water is made up of many different sources of water. We work hard to protect our water and water quality. Find out about each of our reservoirs, how much they contribute to the system and how you can visit them.

SAN ANDREAS

RESERVOIR
FUN FACT:

As the name would suggest, the San
Andreas fault runs through the Reservoir,
and the dam holding back the reservoir
survived the 1906 earthquake. The
6-mile long Sawyer Camp Trail links San
Andreas and Crystal Springs reservoirs.

SAN ANTONIO

RESERVOIR
LAKE

ELEANOR
FUN FACT:

Because of differences in elevation and
water levels, water can be moved from
Lake Eleanor to Cherry Lake through the
Eleanor-Cherry Diversion Tunnel, resulting
in a unique opportunity for highly efﬁ cient
hydroelectric power generation.

PILARCITOS

RESERVOIR

CRYSTAL SPRINGS

RESERVOIR
CHERRY
LAKE

CALAVERAS

RESERVOIR

HETCH HETCHY

RESERVOIR
FUN FACT:

This reservoir, impounded by Turner Dam,
was ﬁ rst sited as a water supply source in
1875 by the Spring Valley Water Company.

It was impounded in 1964 by Turner Dam,
named after former General Manager of
Hetch Hetchy, James H. Turner.

FUN FACT:

Completed in 1866, this reservoir was
the ﬁ rst in our system and initially built
by the Spring Valley Water company
primarily serves water to Half Moon
Bay, though at one point it did store
water for San Francisco too.

FUN FACT:

This is the only lake in our system
where recreational boating is permitted
on the water itself, as this is only an
emergency supply. Maintained in
partnership with the US Forest Service,
Cherry Lake is a popular recreation
spot for locals and visitors alike.

FUN FACT:

O’Shaughnessey Dam which holds
back the Hetch Hetchy Reservoir,
was initially completed in 1923.

It was raised a further 85 feet in
1938 to the height it currently
stands, which is 430 feet.

FUN FACT:

This is the largest of our East
Bay reservoirs. During the recent
construction of the new dam at
Calaveras, prehistoric whale teeth
were found in the ground some 60
miles from the Paciﬁ c Ocean.

FUN FACT:

One of the most accessible reservoirs
of ours to visit from San Francisco,
Crystal Springs offers the opportunity
to walk, hike, and even attend docent
lead bike tours along the trails that
surround the water itself.

A watershed is a land
area that collects and
channels rainfall and
snowmelt by gravity to
creeks, streams, and
rivers, and eventually to
common outﬂ ow points
such as reservoirs,
bays, and the ocean.

GET FAMILIAR WITH OUR WATERSHEDS

QUINOLINE MONITORING

SPECIAL

HEALTH NEEDS
TORING

MONITORING OF PER-

AND POLYFLUOROALKYL

SUBSTANCES (PFAS)
PFAS is a group of approximately 5,000 man-made chemicals used in a variety of industries and consumer products. These chemicals are widely present in the environment and human body. In order to determine the impact of PFAS on the water we provide to our customers, we conducted a round of PFAS monitoring in 2019.

This monitoring effort, done on a voluntary basis, helped to determine whether PFAS was present in any form in any of our water supply, transmission or distribution systems. Using the State’s stringent sampling procedures and based on the currently approved/certi ﬁ ed method of analysis for 18 PFAS contaminants, we con ﬁ rmed no PFAS were detected in our water sources. We did ﬁ nd a trace amount of one PFAS contaminant in 20 samples collected in our distribution system. We suspect the plumbing seal component in the sample tap may be a source of the only detected contaminant, ADONA, found at a level of 2.7 parts per trillion. We plan to conduct another round of PFAS monitoring in late 2020 or early 2021 when a new USEPA method of analysis is available at our contract laboratory. For additional information about PFAS, visit our website at sfwater.org/quality. View the factsheet here, the SWRCB-DDW website waterboards.ca.gov/pfas, and/or USEPA website epa.gov/pfas.

Quinoline is a chemical compound that was commonly used in the coal-tar lining of drinking water pipes to prevent corrosion.

In order to conﬁ rm the safe distribution of water, and in conjunction with the San Francisco Regional Water System, we conducted a special round of voluntary monitoring for quinoline. The monitoring was part of our assessment to determine the source(s) of quinoline from anywhere in our supply, transmission and distribution systems.

Our monitoring results conﬁ rmed the absence of quinoline in our system’s raw water; in other words the results were “non-detect.” We did ﬁ nd low levels of quinoline in four locations in our distribution system; the same locations where low levels were found in 2018, during monitoring done in compliance with the USEPA’s 4th Unregulated Contaminant Monitoring Rule (UCMR4). You may access our UCMR4 water quality data here, and visit the USEPA website epa.gov/dwucmr for information about UCMR4.

Some people may be more vulnerable to contaminants in drinking water than the general population. Immuno-compromised persons, such as those with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly people and infants, can be particularly at risk from infections.

Such individuals should seek advice about drinking water from their healthcare providers. USEPA/CDC guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the USEPA’s Safe Drinking Water Hotline 1-800-426-4791 or at epa.gov/safewater.

WATER FACT:

Planning for the future: our
Water Innovations Program is
implementing and exploring
several efforts, including
PureWaterSF, Expanded
Leak Detection and Brewery
Process Water Reuse
Generally, the sources of drinking water (both tap water and bottled water) include rivers, lakes, oceans, streams, ponds, reservoirs, springs and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals and, in some cases, radioactive material, and can pick up substances resulting from the presence of animals or from human activity. Such substances are called contaminants, and may be present in source water as:

Microbial contaminants, such as viruses and bacteria that may come from sewage treatment plants, septic systems, agricultural livestock operations and wildlife, Inorganic contaminants, such as salts and metals, that can be naturally occurring or result from urban stormwater runoff, industrial or domestic wastewater discharges, oil and gas production, mining or farming,
Pesticides and herbicides that may come from a variety of sources such as agriculture, urban stormwater runoff and residential uses, Organic chemical contaminants, including synthetic and volatile organic chemicals, which are by-products of industrial processes and petroleum production, and can also come from gas stations, urban stormwater runoff, agricultural application and septic systems,
Radioactive contaminants, which can be naturally occurring or be the result of oil and gas production and mining activities.

More information about contaminants and potential health effects can be obtained by calling the USEPA’s Safe Drinking Water Hotline 1-800-426-4791 , or at epa.gov/safewater.

CONTAMINANTS

AND REGULATIONS
Exposure to lead, if present, can cause serious health effects in all age groups, especially for pregnant women and young children. Infants and children who drink water containing lead could have decreases in IQ and attention span and increases in learning and behavior problems. Lead exposure among women who are pregnant increases prenatal risks. Lead exposure among women who later become pregnant has similar risks if lead stored in the mother’s bones is released during pregnancy. Recent science suggests that adults who drink water containing lead have increased risks of heart disease, high blood pressure, kidney or nervous system problems.

Lead in drinking water is primarily from materials and components associated with service lines and home plumbing. There are no known lead service lines in our water distribution system. We are responsible for providing high quality drinking water, but we cannot control the variety of materials used in plumbing components. You share the responsibility for protecting yourself and your family from the lead in your home plumbing. You can take responsibility by identifying and removing lead materials within your home plumbing and taking steps to reduce your family’s risk. Before drinking, ﬂ ush your pipes for several minutes by running your tap, taking a shower, doing laundry or a load of dishes. You can also use a ﬁ lter certiﬁ ed to remove lead from drinking water. If you are concerned about lead in your water you may wish to have your water tested, call 311 or access our website at sfwater.org/leadtest to apply for lead testing analysis at a minimal fee. Information about lead in drinking water, testing methods, and steps you can take to minimize exposure is available at epa.gov/safewater/lead.

DRINKING

WATER AND LEAD

CITY OF

SAN FRANCISCO
2020
ANNUAL
WATER

Q U A L I T Y
REPORT
The San Francisco Public Utilities Commission (SFPUC) produces this annual report detailing where your water comes from, how we treat it, and its overall chemical composition. We do this not only to meet a regulatory requirement but also provide an educational opportunity for you to understand our drinking water operations and public health protection efforts.

We are committed to providing high quality drinking water for all our customers. Our system is large and we work across several counties to maintain the system that delivers potable water for your consumption. In addition to the wider system outside of San Francisco, we also maintain a system of reservoirs within San Francisco. It is our hope that this report will not only provide you with greater knowledge of your water, but also an increased understanding of the considerable skill, talent, and effort of the SFPUC staff that goes into ensuring businesses and residents have reliable access to this precious resource.

We’re proud of our water, and we hope you are too. Throughout this report, you’ll find facts and figures to help expand upon the basic information we’re required to provide. We hope you enjoy getting to know a little more about who we are as an Agency and how you can get involved.

UNDERSTANDING

THIS REPORT
WATER FACT:

Bottled water not only
contributes to plastic waste
and additional carbon
emissions in transportation,
it is also on average
11 TIMES
more expensive than tap
water, and not as heavily
regulated as tap water.

The SFPUC conducts watershed sanitary surveys for the Hetch Hetchy source annually and for the local water sources and UNHHS every five years. The latest sanitary surveys for the local watersheds and the UNHHS watershed were completed in 2021 for the period of 2016-2020. All these surveys together with our stringent watershed protection management activities were completed with support from partner agencies including National Park Service and US Forest Service. The purposes of the surveys are to evaluate the sanitary conditions and water quality of the watersheds and to review results of watershed management activities conducted in the preceding years. Wildfire, wildlife, livestock, and human activities continue to be the potential contamination sources. You may contact the San Francisco District office of the State Water Resources Control Board’s Division of Drinking Water (SWRCB-DDW) at 510-620-3474 to review these reports.

WATERSHED PROTECTION
Our drinking water supply consists of surface water and groundwater that are well protected and carefully managed by the SFPUC. These sources are diverse in both the origin and the location with the surface water stored in reservoirs located in the Sierra Nevada, Alameda County and San Mateo County, and groundwater stored in a deep aquifer located in San Francisco and San Mateo counties. Maintaining this variety of sources is an important component of the SFPUC’s near- and long-term water supply management strategy. A diverse mix of sources protects us from potential disruptions due to emergencies or natural disasters, provides resiliency during periods of drought, and helps us ensure a long-term, sustainable water supply as we address issues such as climate uncertainty, regulatory changes and population growth.

To meet drinking water standards for consumption, water from all of our surface water sources including the upcountry non-Hetch Hetchy sources (UNHHS) undergoes treatment before it is delivered to our customers. Water from the Hetch Hetchy Reservoir is exempt from state and federal filtration requirements but receives the following treatment: ultraviolet light and chlorine disinfection, pH adjustment for optimum corrosion
control, fluoridation for dental health protection, and chloramination for maintaining disinfectant residual
and minimizing the formation of regulated disinfection
byproducts. Water from local Bay Area reservoirs
in Alameda County and San Mateo County is
delivered to Sunol Valley Water Treatment Plant
(SVWTP) and Harry Tracy Water Treatment Plant
(HTWTP), respectively, and is treated by filtration,
disinfection, fluoridation, optimum corrosion control
and taste and odor removal processes.

In 2020, the SFPUC did not use the UNHHS; a small
amount of groundwater from two local wells was added
to our surface water supplies.

OUR DRINKING WATER

SOURCES AND TREATMENT
Source: on.doi.gov/3uNqkjV
WATER FACT:
96%
of the Earth’s
water is saline,
2%
is trapped in the
polar caps as ice.

Humans rely on the remaining
2% for drinking water.

Mandated by State law, water fluoridation is a widely accepted practice proven to be safe and effective for preventing and controlling tooth decay. Our fluoride target level in the water is

0.7 milligram per liter (mg/L, or part per million, ppm), which is consistent with the May 2015 State regulatory guidance on optimal fluoride level. Infants fed formula mixed with water containing fluoride at this level may still have a chance of developing tiny white lines or streaks in their teeth. These marks are referred to as mild to very mild fluorosis, and are often only visible under a microscope. Even in cases where the marks are visible, they do not pose any health risk. The Centers of Disease Control (CDC) considers it safe to use optimally fluoridated water for preparing infant formula. To lessen this chance of dental fluorosis, you may choose to use low-fluoride bottled water to prepare infant formula. Nevertheless, children may still develop dental fluorosis due to fluoride intake from other sources such as food, toothpaste and dental products.

Contact your healthcare provider or SWRCB-DDW if you have concerns about dental fluorosis. For additional information about fluoridation or oral health, visit the SWRCB-DDW website waterboards.ca.gov/drinking_water/certlic/drinkingwater/ Fluoridation.html, the CDC website cdc.gov/fluoridation, or our website sfpuc.org/waterquality.

FLUORIDATION AND

DENTAL FLUOROSIS

WATER QUALITY
The SFPUC regularly collects and tests water samples
from reservoirs and designated sampling points
throughout the system to ensure the water delivered to
you meets or exceeds federal and state drinking water
standards. In 2020, we conducted more than 95,400
drinking water tests in the source, transmission, and
distribution system. This is in addition to the extensive treatment process control monitoring performed by our
certified operators and online instruments.

Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some
contaminants. The presence of contaminants does not
necessarily indicate that water poses a health risk. In order to ensure that tap water is safe to drink, the
United States Environmental Protection Agency (USEPA)
and the SWRCB-DDW prescribe regulations that limit the
amount of certain contaminants in water provided by
public water systems. The U.S. Food and Drug
Administration regulations and California law also
establish limits for contaminants in bottled water that provide the same protection for public health.

WATER FACT:

Ever wondered how
much water it takes
to make breakfast?
On average, it takes about
35 gallons to produce a cup
of coffee beans, 193 gallons
to produce the wheat for a 1lb
loaf of bread, and 50 gallons of
water to produce 2 eggs.

Source: waterfootprint.org
The system that delivers our water is made up of many different sources of water.

We work hard to protect our water and water quality. Find out about each of our reservoirs, how much they contribute to the system and how you can visit them.

SAN ANDREAS

RESERVOIR

SAN ANTONIO

RESERVOIR
LAKE

ELEANOR

PILARCITOS

RESERVOIR

CRYSTAL

SPRINGS

RESERVOIR
CHERRY
LAKE
HETCH
HETCHY

RESERVOIR
FUN FACT:

As the name would suggest, the San Andreas fault runs through the Reservoir, and the dam holding back the reservoir survived the 1906 earthquake. The 6-mile long Sawyer Camp Trail links San Andreas and Crystal Springs reservoirs.

FUN FACT:

Although the current lake was created by the damming of the Eleanor Creek in 1918, there was a smaller natural
lake located at the same site, and bearing the same name.

Today, visitors can take advantage of trails primarily used for moderate hikes as well as the campground.

FUN FACT:

Located near the town of Sunol in Alameda County, This
reservoir was impounded in 1964 by Turner Dam, named
after former General Manager of Hetch Hetchy, James H.

Turner. Like Calaveras, it is closed to the public.

FUN FACT:

Construction of Pilarcitos Dam began in 1862, and was
completed in 1866. It was raised in 1867 and 1874. The
dam is an earth fill dam with a clay puddle core, and a height of 95 feet from foundation to crest. The reservoir has a capacity of just over 1 billion gallons. It serves as a key water supply for Half Moon Bay.

FUN FACT:

This is the only lake in our system where recreational boating is permitted on the water itself, as this is only an emergency supply.

Maintained in partnership with the US Forest Service, Cherry Lake is a popular recreation spot for locals and visitors alike.

FUN FACT:

The name of our largest reservoir is Miwok for “Valley of the Two Trees”, which refers to a pair of pines that once stood at the head of Hetch Hetchy Valley. Miwok names are still used throughout the area, including the two waterfalls Tueeulala Fall, Wapama Fall, and Kolana Rock.

FUN FACT:

The largest of our East Bay reservoirs, Calaveras is located near a seismically active fault. The original dam was built in 1925, and was recently replaced along with several upgrades to improve our ability to better manage the watershed’s biodiversity.

FUN FACT:

Actually consisting of two reservoirs, Upper and Lower
Crystal Springs together provide one of the most accessible watersheds to visit offering the opportunity to walk, hike, and even attend docent lead bike tours along nearby trails.

GET FAMILIAR WITH

OUR WATERSHEDS

CALAVERAS

RESERVOIR
A watershed is a land area
that collects and channels
rainfall and snowmelt by
gravity to creeks, streams,
and rivers, and eventually
to common outflow points
such as reservoirs, bays,
and
the ocean.

SPECIAL HEALTH NEEDS

PER- AND POLYFLUOROALKYL

SUBSTANCES (PFAS)
PFAS is a group of approximately 5,000 man-made, persistent chemicals used in a variety of industries and consumer products. We previously reported that a voluntary round of PFAS monitoring at our surface water sources and some groundwater wells was conducted in 2019. The objective is to identify if our supply sources and water in the distribution system are impacted by PFAS. No PFAS was detected in our water sources; only one PFAS contaminant, ADONA, was slightly detected at a level of 2.7 parts per trillion in our distribution system. In 2020, another round of voluntary monitoring for PFAS was completed for the two new groundwater wells in the Golden Gate Park; no PFAS contaminants were detected. Considering a new PFAS analytical method recently adopted by the USEPA for some more PFAS contaminants, we plan to conduct another round of PFAS monitoring in 2021. For additional information about PFAS, visit our website at sfpuc.org/waterquality , SWRCB-DDW website waterboards.ca.gov/pfas , and/or USEPA website epa.gov/pfas .

Some people may be more vulnerable to contaminants in drinking water than the general population.

Immuno-compromised persons, such as those with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, some elderly people and infants, can be particularly at risk from infections.

These people should seek advice about drinking water from their healthcare providers. USEPA/CDC guidelines on appropriate means to lessen the risk of infection by Cryptosporidium and other microbial contaminants are available from the USEPA’s Safe Drinking Water Hotline 800-426-4791 or at epa.gov/safewater.

BORON DETECTION

ABOVE NOTIFICATION

LEVEL IN SOURCE WATER
In 2020, boron was detected at a level of 1.06 ppm in the raw water stored in Pond F3 East, an approved source in Alameda Watershed. This detection is lower than those in the past, and is slightly above the California Notification level (NL). Boron is an element in nature, and is typically released into air and water when soils and rocks naturally weather. Currently there is no drinking water standard for this naturally-occurring contaminant.

WATER FACT:

The cost of SF tap
water averages at
$0.002

PER GALLON
Generally, the sources of drinking water (both tap water and bottled water) include rivers, lakes, oceans, streams, ponds, reservoirs, springs and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals and, in some cases, radioactive material, and can pick up substances resulting from the presence of animals or from human activity. Such substances are called contaminants, and may be present in source water as:

More information about contaminants and potential health effects can be obtained by calling the USEPA’s Safe Drinking Water Hotline 800-426-4791 , or at epa.gov/safewater.

CONTAMINANTS

AND REGULATIONS
Exposure to lead, if present, can cause serious health effects in all age groups, especially for pregnant women and young children. Infants and children who drink water containing lead could have decreases in IQ and attention span and increases in learning and behavior problems. The children of women who are exposed to lead before or during pregnancy can have increased risk of these adverse health effects. Adults can have increased risks of heart disease, high blood pressure, kidney or nervous system problems.

Lead in drinking water is primarily from materials and components associated with service lines and home plumbing. We are responsible for providing high quality drinking water and removing lead pipes, but we cannot control the variety of materials used in plumbing components in your home. You share the responsibility for protecting yourself and your family from the lead in your home plumbing. You can take responsibility by identifying and removing lead materials within your home plumbing and taking steps to reduce your family’s risk. When your water has been sitting for several hours, you can minimize the potential for lead exposure by flushing your pipes for several minutes, such as running your tap, taking a shower, doing laundry or a load of dishes, before using water for drinking and cooking. You can also use a filter certified by an American National Standards Institute accredited certifier to remove lead from drinking water. If you are concerned about lead in your water you may wish to have your water tested, call 311 or access our website at sfpuc.org/lead to apply for lead testing analysis at a minimal fee.

Information about lead in drinking water, testing methods, and steps you can take to minimize exposure is available at epa.gov/safewater/lead.

DRINKING

WATER AND LEAD
WATER FACT:

Since 2010, the SFPUC has
funded the installation of over
170 Drink-Tap Stations,
including 12 installed in
January 2021 in collaboration
with neighborhood groups and
the City’s COVID Command
Center to support COVID
recovery efforts.

We assisted a total of 190 public and private K-12 schools in lead monitoring for their tap water between 2017 and 2019. School monitoring data can be found at sfpuc.org/lead. Presently we are working with San Francisco Unified School District to develop a voluntary, 5-year recurring monitoring program to provide continued support to local schools in addressing lead in their tap water. However, due to COVID-19 situation, discussions with the school district has been postponed.

LEAD IN SCHOOLS
We conducted our triennial Lead and Copper Rule (LCR)
monitoring in 2018, and these tap sampling results are
accessible at sfpuc.org/waterquality . LCR monitoring occurs at household taps within residences. The results do not represent lead and copper concentrations throughout the distribution system. The next round of LCR monitoring will be in 2021.

LEAD AND

COPPER TAP

SAMPLING RESULTS

LEAD USER

SERVICE LINE (LUSL)
In addition to our water source protection efforts, we continue the following programs to minimize customer exposure to lead in water:
• Replacing the remaining 2% of brass meters with
lead
-free automated water meters
• Annual monitoring for lead at transmission system’s entry points (moni
toring results in 2020 were non-detect)
• Offering in partnership with the San Francisco Department of Publ
ic Health free lead test vouchers for clients enrolled in the Women
, Infants and Children (WIC) program
• Offering low-cost water tests for lead at $25 per tap. To request a test
, call 311 or visit our website sfpuc.org/lead for an
appl
ication form
In 2020, we continued inspecting and characterizing the 10,912 service lines of unknown material and 4,524 service lines suspected of having lead components, as known as LUSLs. These figures were first reported to SWRCB-DDW in July 2018. Results of field investigations, as well as a schedule to replace known LUSLs, were reported to the SWRCB-DDW in July 2020. As of April 2021, there remains 4,481 service lines of unknown material and 4,434 LUSLs to be field verified by the end of 2022. The LUSL inventory and map are accessible to public and can be found at sfpuc.org/waterquality. Investigations at schools and licensed child care centers are prioritized in the schedule. Our policy is to remove and replace any LUSL promptly if it is discovered during pipeline repair and/or maintenance. We are also conducting a pilot study to determine the effects of the lead components on lead levels at customer taps.

Only 14 countries
report high levels
of community and
user participation for
collaborative management
and decision-making.

Source: : UN Water: SDG6 Water
and Sanitation for All, 2021.
bit.ly/3mOgag7
WATER FACT:

KEY WATER QUALITY TERMS
The following are definitions of key terms referring to standards and goals of water quality noted on the data table.

Public Health Goal (PHG): The level of a contaminant in drinking water below which there is no known or expected risk to health. PHGs are set by the California Environmental Protection Agency.

Maximum Contaminant Level Goal (MCLG) : The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs are set by the USEPA.

Maximum Contaminant Level (MCL) : The highest level of a contaminant that is allowed in drinking water. Primary MCLs are set as close to the PHGs or MCLGs as is economically and technologically feasible. Secondary MCLs (SMCLs) are set to protect the odor, taste, and appearance of drinking water.

Maximum Residual Disinfectant Level (MRDL): The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.

Maximum Residual Disinfectant Level Goal (MRDLG) : The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGs do not reflect the benefits of the use of disinfectants to control microbial contaminants.

Primary Drinking Water Standard (PDWS): MCLs, MRDLs, and TT (see below) for contaminants that affect health along with their monitoring and reporting requirements, and water treatment requirements.

Regulatory Action Level : The concentration of a contaminant which, if exceeded, triggers treatment or other requirements that a water system must follow.

Treatment Technique (TT): A required process intended to reduce the level of a contaminant in drinking water.

Turbidity: A water clarity indicator that measures cloudiness of the water, and is also used to indicate the effectiveness of the filtration system. High turbidity can hinder the effectiveness of disinfectants.

Cryptosporidium is a parasitic microbe found in most surface water. We regularly test for this waterborne pathogen and found it at very low levels in source water and treated water in 2020. However, current test methods approved by the USEPA do not distinguish between dead organisms and those capable of causing disease. Ingestion of Cryptosporidium may produce symptoms of nausea, abdominal cramps, diarrhea, and associated headaches.

Cryptosporidium must be ingested to cause disease, and it may be spread through means other than drinking water.

OUR WATER IN THE COMMUNITY:

THE WESTSIDE ENHANCED

WATER RECYCLING PROJECT
On the west side of San Francisco, we are aiming to save up to 2 million gallons per day (mgd) on average of drinking water that is currently used for non-drinking purposes such as irrigation and lake fill. Recycled water will be delivered for these uses through a system of pipelines, pump stations, storage tanks and reservoirs.

The system will bring recycled water from the recycled water treatment facility to Golden Gate Park, Lincoln Park Golf Course, the Presidio Golf Course and other landscaped areas for irrigation.

Almost 8 miles of new recycled water pipelines have been constructed mostly under City streets. These pipelines will bring recycled water from the newly constructed treatment facility to sites where the water will be used. Construction has also begun on an underground recycled water reservoir, and above-ground recycled water pump station in Golden Gate Park that will pump recycled water to Lincoln Park and the Presidio.

SAN FRANCISCO WATER SYSTEM-WATER QUALITY DATA FOR 2020
The table below lists detected contaminants in our drinking water in 2020 and the information about their typical sources.

Contaminants below detection limits for reporting are not shown, in accord with regulatory guidance. We hold a SWRCB-DDW monitoring waiver for some contaminants in our surface water supply and therefore their monitoring frequencies are less than annual. Visit sfpuc.org/waterquality for a list of all water quality parameters we monitored in raw water and treated water in 2020.

FOOTNOTES ON SAN FRANCISCO WATER SYSTEM - WATER QUALITY DATA:
(1) These are monthly average turbidity values measured every 4 hours daily. (2) There is no turbidity MCL for filtered water. The limits are based on the TT requirements for filtration systems. (3) This is the highest locational running annual average value. (4) Total organic carbon is a precursor for disinfection byproduct formation. The TT requirement applies to the filtered water from the SVWTP only. (5) The SWRCB -DDW recommended an optimal fluoride level of 0.7 ppm be maintained in the treated water. In 2020, the range and average of the fluoride levels were

0.6 ppm - 0.9 ppm and 0.7 ppm, respectively. (6) Natural fluoride in the Hetch Hetchy source was ND. Elevated fluoride levels in the raw water at

DETECTED CONTAMINANTS UNIT MCL PHG

OR (MCLG)

RANGE OR

LEVEL FOUND

AVERAGE
OR [MAX] MAJOR SOURCES IN DRINKING WATER

TURBIDITY
Unfiltered Hetch Hetchy Water NTU 5 N/A 0.2 - 0.5 (1) [1.3] Soil runoff Filtered Water from Sunol Valley
Water Treatment Plant (SVWTP)
NTU
-
1 (2)
Min 95% of
samples
≤0.3 NTU (2)
N/A
N/A
-

99.8% - 100%
[0.4]
-
Soil runoff
Soil runoff
Filtered Water from Harry Tracy
Water Treatment Plant (HTWTP)
NTU
-
1 (2)
Min 95% of
samples
≤0.3 NTU (2)
N/A
N/A
-
100%
[0.1]
-
Soil runoff
Soil runoff

DISINFECTION BY-PRODUCTS AND PRECURSOR
Total Trihalomethanes ppb 80 N/A 13 - 43 [43]
(3) By-product of drinking water disinfection
Haloacetic Acids ppb 60 N/A 10 - 33 [35] (3) By-product of drinking water disinfection Total Organic Carbon (4) ppm TT N/A 1.7 - 3.4 2.9 Various natural and man-made sources

MICROBIOLOGICAL
Total Coliform - NoP ≤5.0% of
monthly samples (0) - [0.6%] Naturally present in the environment Giardia lamblia cyst/L TT (0) 0 - 0.05 0.01 Naturally present in the environment

INORGANICS
Fluoride (source water) (5) ppm 2.0 1 ND - 0.7 0.3 (6) Erosion of natural deposits; water additive to promote strong teeth Chloramine (as chlorine) ppm MRDL = 4.0 MRDLG = 4 0.1 - 3.5 [2.5] (7) Drinking water disinfectant added for treatment

CONSTITUENTS WITH

SECONDARY STANDARDS UNIT SMCL PHG RANGE AVERAGE MAJOR SOURCES OF CONTAMINANT Chloride ppm 500 N/A <3 - 15 9 Runoff / leaching from natural deposits Specific Conductance µS/cm 1600 N/A 30 - 260 160 Substances that form ions when in water Sulfate ppm 500 N/A 1 - 34 17 Runoff / leaching from natural deposits Total Dissolved Solids ppm 1000 N/A <20 - 137 72 Runoff / leaching from natural deposits Turbidity NTU 5 N/A ND - 0.2 ND Soil runoff
LEAD AND COPPER (8) UNIT AL PHG RANGE 90TH

PERCENTILE MAJOR SOURCES IN DRINKING WATER
Copper ppb 1300 300 ND - 103 64 Internal corrosion of household water plumbing systems Lead ppb 15 0.2 <1 - 90 6 Internal corrosion of household water plumbing systems

OTHER WATER QUALITY

PARAMETERS

UNIT ORL RANGE AVERAGE KEY
Alkalinity (as CaCO3) ppm N/A 6.7 - 138 55 < / ≤ = less than / less than or equal to AL = Action Level
Max = Maximum
Min = Minimum
N/A = Not Available
ND = Non-Detect
NL = Notification Level
NoP = Number of Coliform-Positive Sample
NTU = Nephelometric Turbidity Unit
ORL = Other Regulatory Level
ppb = part per billion
ppm = part per million
µS/cm = microSiemens/centimeter
Calcium (as Ca) ppm N/A 2.9 - 22 12
Chlorate (9) ppb 800 (NL) 67 - 1200 262
Hardness (as CaCO3) ppm N/A 8.0 - 79 45
Magnesium ppm N/A 0.2 - 6.8 4.0
pH - N/A 8.1 - 9.8 9.3
Potassium ppm N/A 0.3 - 1.3 0.8
Silica ppm N/A 2.8 - 7 4.8
Sodium ppm N/A 2.4 - 22 14
Strontium ppb N/A 14 - 242 110
the SVWTP and HTWTP were attributed to the transfer of fluoridated Hetch Hetchy water into the local reservoirs. (7) This is the highest running annual average value. (8) The most recent Lead and Copper Rule monitoring was in August 2018. Two of the 90 site samples collected at consumer taps had lead concentrations above the AL. (9) The detected chlorate in the treated water is a degradation product of sodium hypochlorite, which we use for water disinfection.

San Francisco Local Groundwater - Water Quality Data for Year 2020 Treated Water
(Sunset
Reservoir)

DETECTED CONTAMINANTS UNIT MCL
PHG
OR
(MCLG)
RANGE

OR LEVEL
FOUND

AVERAGE MAJOR SOURCES IN DRINKING WATER

INORGANICS
Chromium (VI) ppb N/A (1) 0.02 ND - 1.3 ND Leaching from natural deposits; waste discharges from electroplating
Nitrate (as nitrogen) ppm 10 10 ND - 0.5 ND Landscape fertilizers and leaked wastewater Fluoride ppm 2.0
(Natural-Source)
1 0.7 0.7 Erosion of natural deposits; water additive to promote strong teeth

DETECTED CONTAMINANTS UNIT SMCL PHG
RANGE

OR LEVEL
FOUND

AVERAGE MAJOR SOURCES OF CONTAMIANT

CONSTITUENTS WITH SECONDARY STANDARDS
Chloride ppm 500 N/A 5.5 - 6.2 5.9 Runoff / leaching from natural deposits Color Unit 15 N/A 5 5 Naturally-occurring organic materials Specific Conductance µS/cm 1600 N/A 57 - 325 138 Substances that form ions when in water Sulfate ppm 500 N/A 2.3 - 3.5 2.9 Runoff / leaching from natural deposits Total Dissolved Solids ppm 1000 N/A 25 - 73 50 Runoff / leaching from natural deposits Turbidity NTU 5 N/A 0.1 0.1 Soil runoff

OTHER WATER QUALITY

PARAMETERS UNIT ORL RANGE AVERAGE
Strontium ppb N/A 22 - 28 25
Raw Water
(San Francisco
Local
Groundwater
Wells)

DETECTED CONTAMINANTS UNIT MCL
PHG
OR
(MCLG)

RANGE AVERAGE MAJOR SOURCES IN DRINKING WATER
INORGANICS (2)
Chromium (VI) ppb N/A (1) 0.02 2.5 - 23 14.7 Leaching from natural deposits; waste discharges from electroplating
Chromium (Total) ppb 50 (100) ND - 21 10.7 Erosion of natural deposits; discharge from electroplating
Nitrate (as nitrogen) ppm 10 10 3.1 - 9.4 5.8 Landscape fertilizers and leaked wastewater

VOLATILE ORGANICS

Carbon tetrachloride (3) ppb 0.5 0.1 0.6 - 0.9 0.7 Commercial and industrial solvent used in dry cleaning prior to 1960
Tetrachloroethylene
(4) ppb 5 0.06 1.5 - 2.2 1.9 Commercial and industrial solvent used in dry cleaning prior to 2010, and as a metal degreaser in
auto shops and metalworking industries

OTHER WATER QUALITY

PARAMETERS UNIT ORL

RANGE AVERAGE
pH - N/A 7.3 - 8.3 7.8
Strontium ppb N/A 131 - 187 159
Vanadium ppb 50 (NL) 5.9 - 7 6.5
FOOTNOTES ON SAN FRANCISCO LOCAL GROUNDWATER - WATER QUALITY DATA:
(1) Chromium (VI) is currently regulated by the SWRCB-DDW under a MCL of 50 ppb for total chromium. The results of total chromium monitoring in treated water were ND in 2020. (2) The concentration ranges and averages of these contaminants are indicative of the raw groundwater quality prior to blending, which is approved by SWRCB-DDW as a treatment for groundwater. They are not representative of water in the distribution system. In 2020, only two wells (Lake Merced Well and West Sunset Well) delivered groundwater to the distribution system intermittently. (3) Carbon tetrachloride was detected above the MCL in the raw water at South Sunset Well; however, the well was not in operation throughout 2020. (4) Tetrachloroethylene was slightly detected in the raw water at Golden Gate Central Well, which supplied Golden Gate Park throughout 2020 for irrigation only.

P.O. Box 7369
San Francisco, CA 94120-7369
@MySFPUC
This report contains important information about your drinking water. Translate it, or speak with someone who understands it.

Este informe contiene información muy importante sobre su agua potable. Tradúzcalo o hable con alguien que lo entienda bien.

Mahalaga ang impormasyong ito. Mangyaring ipasalin ito.

Cé rapport contient des information importantes concernant votre eau potable. Veuillez traduire, ou parlez avec quelqu’ un qui peut le comprendre.

Dieser Bericht enthält wichtige Information über Ihr Trinkwasser. Bitte übersetzen Sie ihn oder sprechen Sie mit jemandem, der ihn versteht.

Questo rapporto contiene informazioni importanti che riguardano la vostra aqua potabile.

Traducetelo, o parlate con una persona qualificata in grado di spiegarvelo. 此份水質報告，內有重要資訊。請找他人為你翻譯和解說清楚。
Этот отчет содержит важную информацию о вашей питьевой воды. Переведите его или поговорите с тем, кто это понимает.
この報告書には上水道に関する重要な情報が記されております。翻訳を御依頼なされ
るか、内容をご理解なさっておられる方にお尋ね下さい。
Sophie Maxwell, PRESIDENT
Anson Moran, VICE PRESIDENT
Tim Paulson, COMMISSIONER
Ed Harrington, COMMISSIONER
Newsha K. Ajami, COMMISSIONER
San Francisco Public Utilities Commission
Every day we deliver high-quality drinking water to 2.7 million people in San Francisco, Alameda, Santa Clara and San Mateo counties. We generate clean, reliable hydroelectricity that powers 100% of
San Francisco’s vital services, including police and fire stations, street lights, Muni, SF General Hospital and more.

This report contains important information about our drinking water. Please contact SFPUC Communications at 415-554-3289 or email [email protected] for assistance.

Este informe contiene información muy importante sobre su agua para beber. Favor de comunicarse SFPUC a 415-554-3289 para asistirlo en español
con alguien que lo entienda bien.
此份水質報告，內有重要資訊。請找他人為你翻譯和解說清楚。
Interested in learning
more? Our Commission
meets monthly, and more
details are on our website
sfpuc.org/commission

CITY OF SAN FRANCISCO
2021

ANNUAL WATER

QUALITY REPORT

The San Francisco Public Utilities Commission (SFPUC) provides 2.7 million customers in cities and towns across the region with water so pure that it meets all federal and state standards. Through careful stewardship of both our natural resources and our infrastructure, every drop that arrives at your home or business is clean and of the highest quality. However, long-term climate change and recent years of reduced rainfall require all of us to rethink the way we use this precious resource.

In response to the three years of nearly statewide drought, in November 2021 the SFPUC declared a Water Shortage Emergency to help extend our water supplies. The SFPUC is asking all of our customers in San Francisco, San Mateo, Santa Clara, and Alameda counties to reduce their water use by cutting waste. Visit sfpuc.org/drought for ways you can help.

The SFPUC produces a Water Quality Report every year in order to provide speciﬁ c information about where your water comes from, how we treat it, and its overall chemical composition. We do this not only to meet regulatory requirements but also to provide you with clear and important information about our drinking water operations and our public health protection efforts.

We are committed to providing high quality drinking water for all our customers. The SFPUC operates and maintains a water system that extends over a hundred miles across several counties to deliver potable water for consumption by millions of individuals. In addition to the system of reservoirs within San Francisco, the SFPUC also maintains a wider system of reservoirs and pipelines on the Peninsula, in the South Bay, and upcountry in the Yosemite Valley. It is our hope that this report will not only provide you with greater knowledge of your water, but also an increased conﬁ dence in the skills, talents, and efforts of our staff that ensure the highest quality water for every one of our customers.

We’re proud of our water, and we need your help in conserving it. Throughout this report, you’ll ﬁ nd facts and ﬁ gures to help expand upon the basic information we’re required to provide. We hope you enjoy getting to know a little more about who we are as an Agency and how you can help make a difference.

Understanding This Report
A leaking faucet wastes
hundreds of gallons of
water a month. Fix leaks
to save water and avoid
bill increases.

FIX LEAKS

RIGHT AWAY
WAYS

TO SAVE
Our Tap Water
The SFPUC conducts watershed sanitary surveys for the Hetch Hetchy source annually and for non-Hetch Hetchy surface water sources every ﬁ ve years. The latest sanitary surveys for the non-Hetch Hetchy watersheds were completed in 2021 for the period of 2016-2020. All these surveys, together with SFRWS’s stringent watershed protection management activities, were completed with support from partner agencies including National Park Service and US Forest Service. The purposes of the surveys are to evaluate the sanitary conditions and water quality of the watersheds and to review results of watershed management activities conducted in the preceding years. Wildﬁ re, wildlife, livestock, and human activities continue to be the potential contamination sources. You may contact the San Francisco District ofﬁ ce of the State Water Resources Control Board’s Division of Drinking Water (SWRCB) at 510-620-3474 for more information.

Protection of Watersheds
Most of our drinking water supply comes from the San Francisco Regional Water System (SFRWS), which is the wholesale system owned and operated by the SFPUC. The supply consists of surface water and groundwater that are well protected and carefully managed. These sources are diverse in both origin and location with the surface water stored in reservoirs located in the Sierra Nevada, Alameda County and San Mateo County, as well as groundwater stored in a deep aquifer located in the northern part of San Mateo County and the western side of San Francisco. Maintaining this variety of sources is an important component of the SFPUC’s near- and long-term water supply management strategy. A diverse mix of sources protects us from potential disruptions due to emergencies or natural disasters, provides resiliency during periods of drought, and helps us ensure a long-term, sustainable water supply as we address issues such as climate uncertainty, regulatory changes, and population growth.

To meet drinking water standards for consumption, all surface water supplies including the upcountry non-Hetch Hetchy sources (UNHHS) undergo treatment by the SFRWS before it is delivered. Although the water from Hetch Hetchy Reservoir is exempt from state and federal ﬁ ltration requirements, it receives the following treatment: disinfection using ultraviolet light and chlorine, pH adjustment for optimum corrosion control, ﬂ uoridation for dental health protection, and chloramination for maintaining disinfectant residual and minimizing the formation of regulated disinfection byproducts. Water from local Bay Area reservoirs in Alameda County and UNHHS is delivered to Sunol Valley Water Treatment Plant (SVWTP); whereas water from local reservoirs in San Mateo County is delivered to Harry Tracy Water Treatment Plant (HTWTP).

Water treatment at these plants consist of ﬁ ltration, disinfection, ﬂ uoridation, optimum corrosion control, and taste and odor removal.

In 2021, no UNHHS water was used. However, a small amount of groundwater was added to our surface water supplies through blending in the transmission pipelines and Sunset Reservoir.

Our Drinking Water
Sources and Treatment

Fluoridation and
Dental Fluorosis
Water Quality
Mandated by State law, water ﬂ uoridation is a widely accepted practice proven safe and effective for preventing and
controlling tooth decay. Our ﬂ uoride target level in the water is

0.7 milligram per liter (mg/L, or part per million, ppm), which is consistent with the May 2015 State regulatory guidance on optimal ﬂ uoride level. Infants fed formula mixed with water containing ﬂ uoride at this level may still have a chance of developing tiny white lines or streaks in their teeth. These marks are referred to as mild to very mild ﬂ uorosis, and are often only visible under a microscope. Even in cases where the marks are visible, they do not pose any health risk. The Centers of Disease Control (CDC) considers it safe to use optimally ﬂ uoridated water for preparing infant formula. To lessen this chance of dental ﬂ uorosis, you may choose to use low-ﬂ uoride bottled water to prepare infant formula. Nevertheless, children may still develop dental ﬂ uorosis due to ﬂ uoride intake from other sources such as food, toothpaste, and dental products.

Contact your healthcare provider or the SWRCB if you have concerns about dental ﬂ uorosis. For additional information about ﬂ uoridation or oral health, visit the SWRCB website waterboards.ca.gov/drinking_water/certlic/drinkingwater/ Fluoridation.html , the CDC website cdc.gov/ﬂ uoridation, or our website sfpuc.org/tapwater.

We regularly collect and test water samples from reservoirs and designated sampling points throughout the systems to ensure the water delivered to you meets all federal and state drinking water standards. In 2021, we conducted more than 95,190 drinking water tests in the source, transmission, and distribution system. This is in addition to the extensive treatment process control monitoring performed by our
certiﬁ ed operators and online instruments.

Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some
contaminants. The presence of contaminants does not
necessarily indicate that water poses a health risk. To ensure that tap water is safe to drink, the United States Environmental Protection Agency (USEPA) and the SWRCB
prescribe regulations that limit the amount of certain
contaminants in water provided by public water systems. The U.S. Food and Drug Administration regulations and California law also establish limits for contaminants in bottled water that provide the same protection for public health.

Showers can use up to
a gallon a minute, so
shorter showers really
save. Get a water-efﬁ cient
showerhead before you
lather, rinse, and repeat.

SHOWERS
WAYS

TO SAVE

The system that delivers our water is made up of many different sources of water. We work hard to protect our water and water quality. Find out about each of our reservoirs, how much they contribute to the system and how you can visit them.

FUN FACT:

As the name would suggest,
the San Andreas fault runs
through the reservoir, and the
dam holding back the reservoir
survived the 1906 earthquake.

The 6-mile long Sawyer Camp
Trail links San Andreas and
Crystal Springs reservoirs.

FUN FACT:

Although the current lake was
created by the damming of the
Eleanor Creek in 1918, there was
a smaller natural lake located at
the same site, and bearing the
same name. Today, visitors can
take advantage of trails primarily
used for moderate hikes as well
as the campground.

FUN FACT:

Located near the town of
Sunol in Alameda County, this
reservoir was impounded in
1964 by Turner Dam, named
after former General Manager
of Hetch Hetchy, James H.

Turner. Like Calaveras, it is
closed to the public.

FUN FACT:

Construction of Pilarcitos
Dam began in 1862, and was
completed in 1866. It was raised
in 1867 and 1874. The dam is an
earth ﬁ ll dam with a clay puddle
core, and a height of 95 feet from
foundation to crest. The reservoir
has a capacity of just over 1
billion gallons. It serves as a key
water supply for Half Moon Bay.

FUN FACT:

Cherry Lake is a popular
recreation spot for
local and visitors alike.

It provides emergency
backup water supply to our
system, and recreational
boating is permitted on the
water itself. This reservoir is
maintained in partnership
with US Forest Service.

FUN FACT:

The name of our largest
reservoir ikely comes
from the Miwok word,
hatchhatchie, meaning
“edible grasses.” Miwok
names are still used
throughout the area,
including the two waterfalls
Tueeulala Fall, Wapama
Fall, and Kolana Rock.

FUN FACT:

The largest of our East Bay
reservoirs, Calaveras is
located near a seismically
active fault. The original dam
was built in 1925, and was
recently replaced along with
several upgrades to improve
our ability to better manage
the watershed’s biodiversity.

FUN FACT:

Actually consisting of two
reservoirs, Upper and Lower
Crystal Springs together
provide one of the most
accessible watersheds to
visit offering the opportunity
to walk, hike, and even
attend docent lead bike
tours along nearby trails.

Get Familiar With
Our Watersheds
A watershed is a land area that
collects and channels rainfall
and snowmelt by gravity to
creeks, streams, and rivers, and
eventually to common outﬂ ow
points such as reservoirs, bays,
and the ocean.

CALAVERAS

RESERVOIR
CHERRY
LAKE

CRYSTAL

SPRINGS

RESERVOIR

HETCH HETCHY

RESERVOIR

SAN ANTONIO

RESERVOIR
LAKE

ELEANOR

PILARCITOS

RESERVOIR

SAN ANDREAS

RESERVOIR

ELEANOR
Generally, the sources of drinking water (both tap water and bottled water) include rivers, lakes, oceans, streams, ponds, reservoirs, springs, and wells. As water travels over the surface of the land or through the ground, it dissolves naturally occurring minerals and, in some cases, radioactive material, and can pick up substances resulting from the presence of animals or from human activity. Such substances are called contaminants, and may be present in source water as:

Microbial contaminants, such as viruses and bacteria that may come from sewage treatment plants, septic systems, agricultural livestock operations and wildlife
Inorganic contaminants, such as salts and metals, that can be naturally occurring or result from urban stormwater runoff, industrial or domestic wastewater discharges, oil and gas production, mining, or farming
Pesticides and herbicides that may come from a variety of sources such as agriculture, urban stormwater runoff and residential uses Organic chemical contaminants, including synthetic and volatile organic chemicals, which are by-products of industrial processes and petroleum production, and can also come from gas stations, urban stormwater runoff, agricultural application, and septic systems Radioactive contaminants, which can be naturally occurring or be the result of oil and gas production and mining activities More information about contaminants and potential health effects can be obtained by calling the USEPA’s Safe Drinking Water Hotline 800-426-4791 , or at epa.gov/safewater.

Contaminants
and Regulations
Special Health Needs
Per-and Polyﬂ uoroalkyl
Substances (PFAS)
PFAS is a group of approximately 5,000 man-made, persistent chemicals used in a variety of industries and consumer products. In 2021, we conducted a second round of voluntary monitoring using a new analytical method adopted by the USEPA for some other PFAS contaminants. No PFAS were detected above the SWRCB’s Consumer Conﬁ dence Report Detection Levels in our surface water and groundwater sources. For additional information about PFAS, you may visit SWRCB website waterboards.ca.gov/pfas, SFPUC website sfpuc.org/tapwater, and/or USEPA website epa.gov/pfas.

Some people may be more vulnerable to contaminants in drinking water than the general population. Immuno-compromised persons, such as those with cancer undergoing chemotherapy, persons who have undergone organ transplants, people with HIV/AIDS or other immune system disorders, and some elderly people and infants, can be particularly at risk from infections.

Use water-wise principles when
caring for lawns and gardens
-- select climate appropriate
plants, efﬁ cient irrigation and
conservation-friendly design.

LAWNS AND

GARDENS
WAYS

TO SAVE
Exposure to lead, if present, can cause serious health effects in all age groups, especially for pregnant women and young children. Infants and children who drink water containing lead could have decreases in IQ and attention span and increases in learning and behavior problems. The children of women who are exposed to lead before or during pregnancy can have increased risk of these adverse health effects. Adults can have increased risks of heart disease, high blood pressure, kidney or nervous system problems.

Lead in drinking water is primarily from materials and components associated with service lines and home plumbing. There are no known lead service lines in our water distribution system. We are responsible for providing high quality drinking water and removing lead pipes, but we cannot control the variety of materials used in plumbing components in your home. You share the responsibility for protecting yourself and your family from the lead in your home plumbing. You can take responsibility by identifying and removing lead materials within your home plumbing and by taking steps to reduce your family’s risk. When your water has been sitting for several hours, you can minimize the potential for lead exposure by ﬂ ushing your pipes for several minutes, such as running your tap, taking a shower, doing laundry or a load of dishes, before using water for drinking and cooking. You can also use a ﬁ lter certiﬁ ed by an American National Standards Institute accredited certiﬁ er to remove lead from drinking water. If you are concerned about lead in your water you may wish to have your water tested, call 311 or access our website at sfpuc.org/leadtest to apply for lead testing analysis at a minimal fee. Information about lead in drinking water, testing methods, and steps you can take to minimize exposure is available at epa.gov/safewater/lead.

Drinking Water and Lead
In addition to our water source protection efforts, we continue the following programs to minimize customer exposure to lead in water:
• Replace the remaining 0.33% of brass meters with lead-free automated water meters to the practicable extent • Conduct annual monitoring for lead at the entry points to the SFRWS • Offer in partnership with the San Francisco Department of Public Health free lead test vouchers for clients enrolled in the Women, Infants and Children program
• Offer low-cost water tests for lead for $25 per tap
Lead User Service Line (LUSL)
In July 2020, the SFPUC submitted a 10-year lead component replacement schedule to the SWRCB and began replacing the estimated 1,578 galvanized steel services lines that may have lead whips. The schedule includes ﬁ eld inspection to conﬁ rm the unknown material service lines. If a galvanized service line is found or the unknown material cannot be veriﬁ ed, the service line is scheduled for replacement.

The SFWS created a Lead Service Line Replacement Program with a customer lookup map, which is posted on SFPUC’s website, sfpuc.org/lead. A customer can use the map to identify if the address has an unknown or galvanized service line.

In July 2021, the 10-year lead component replacement schedule was updated with the number of unknowns and galvanized services that remained to be inspected. New changes also reﬂ ected that customers in disadvantaged neighborhood areas would be distributed equitably in the monthly ﬁ eld inspection and replacement schedule. As of May 2022, there are 1,031 galvanized service lines conﬁ rmed and 2,904 ﬁ eld inspections to be done. We also began the preparation of material inventory for customer- side service line: 5207 ﬁ eld inspection were done and 406 service lines were determined as galvanized.

Between 2019 and 2021, staff conducted a pilot study evaluating the lead levels at residences in SFWS where LUSLs were subsequently replaced. A total of 36 participants volunteered for the study, of which the results indicated that lead levels in tap samples after LUSL replacement increased slightly and then dropped to levels lower than the Action Level. Some of these participants still have noticeable lead results in their ﬁ rst 1-liter samples, suggesting that the household plumbing is still a contributor to the lead detected in the tap water. These are consistent with industry ﬁ ndings. See sfpuc.org/lead for the SFWS report on “Impact of Lead Components on Household Lead Levels at the Tap”, dated March 2022.

Presently we are working with San Francisco Uniﬁ ed School District to help develop a long-term, recurring lead monitoring program for the K-12 schools. We are also assisting the school district in completing lead sampling in childcare centers on public school campuses by late 2022.

Lead Tests in Childcare
Facilities and Public Schools
We conducted our triennial Lead and Copper Rule (LCR) monitoring in 2021, when we sample from customer taps rather than our distribution system, and these sampling results are accessible at sfpuc.org/lead . The next round of LCR monitoring will be in 2024.

Lead and Copper
Tap Sampling Results
This report reﬂ ects changes in drinking water regulatory requirements during 2021, in which the SWRCB adopted the California version of the federal Revised Total Coliform Rule. The revised rule, effective on July 1, 2021, maintains the purpose to protect public health by ensuring the integrity of the drinking water distribution system and monitoring for the presence of microbes (i.e., total coliform and E. coli bacteria). Greater public health protection is anticipated, as the revised rule requires water systems that are vulnerable to microbial contamination to identify and ﬁ x problems. Water systems that exceed a speciﬁ ed frequency of total coliform occurrences are required to conduct an assessment to determine if any sanitary defects exist. If found, these must be corrected by the water system.

State Revised Total Coliform Rule
In 2021, we detected carbon tetrachloride at levels above the California MCL in groundwater source at West Sunset Well (WSW). However, water from WSW was blended with treated surface water in Sunset Reservoir and the contaminant was not detected in the blend water that was served to the system. Upon conﬁ rmed detection, we have suspended the operation of WSW indeﬁ nitely.

Carbon Tetrachloride Detection
in Groundwater Source
Landscaping with native
plants attracts beneﬁ cial
bugs and minimizes the
need for chemicals.
sfpuc.org/savewater

OUTDOORS
WAYS

TO SAVE
Key Water Quality Terms
The following are deﬁ nitions of key terms referring to standards and goals of water quality noted on the data table.

Public Health Goal (PHG): The level of a contaminant in drinking water below which there is no known or expected risk to health. PHGs are set by the California Environmental Protection Agency.

Maximum Contaminant Level Goal (MCLG) : The level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs are set by the USEPA.

Maximum Contaminant Level (MCL) : The highest level of a contaminant that is allowed in drinking water. Primary MCLs are set as close to the PHGs or MCLGs as is economically and technologically feasible. Secondary MCLs (SMCLs) are set to protect the odor, taste, and appearance of drinking water.

Maximum Residual Disinfectant Level Goal (MRDLG): The level of a drinking water disinfectant below which there is no known or expected risk to health. MRDLGs do not reﬂ ect the beneﬁ ts of the use of disinfectants to control microbial contaminants.

Primary Drinking Water Standard (PDWS): MCLs and MRDLs for contaminants that affect health along with their monitoring and reporting requirements, and water treatment requirements.

Regulatory Action Level : The concentration of a contaminant which, if exceeded, triggers treatment or other requirements that a water system must follow.

Treatment Technique (TT): A required process intended to reduce the level of a contaminant in drinking water.

Cryptosporidium is a parasitic microbe found in most surface water. We regularly test for this waterborne pathogen and found it at very low levels in source water and treated water in 2021. However, current test methods approved by the USEPA do not distinguish between dead organisms and those capable of causing disease. Ingestion of Cryptosporidium may produce symptoms of nausea, abdominal cramps, diarrhea, and associated headaches. Cryptosporidium must be ingested to cause disease, and it may be spread through means other than drinking water.

Recycling a
Precious Resource
Drinking water is precious – in both drought and downpour. Once it has been treated, wastewater from homes and businesses can have a second life when used for non-drinking purposes such as irrigation and ﬁ lling lakes. Starting in late 2022, highly treated wastewater from our Oceanside Wastewater Treatment Plant will irrigate Golden Gate Park.

This frees up more groundwater to add to our drinking water system, enough to serve 47,000 San Franciscans.

Already, almost 8 miles of dedicated pipelines have been constructed to bring recycled water from the newly constructed treatment facility to these sites. Construction has also begun on an underground recycled water reservoir, and above-ground recycled water pump station in Golden Gate Park that will pump recycled water to Lincoln Park and the Presidio.

Learn more about how we make the most out of every drop at sfpuc.org.

San Francisco Water System - Water Quality Data for 2021 This report is a snapshot of last year’s water quality. The tables below list detected contaminants in our drinking water in 2021 and the information about their typical sources. Contaminants below detection limits for reporting are not shown, in accord with regulatory guidance. The SFRWS holds a SWRCB monitoring waiver for some contaminants in the surface water supply and therefore their monitoring frequencies are less than annual. Visit sfpuc.org/waterquality for a list of all water quality parameters we monitored in raw water and treated water in 2021.

DETECTED CONTAMINANTS UNIT MCL/TT PHG

OR (MCLG)

RANGE OR

LEVEL FOUND

AVERAGE
OR [MAX] TYPICAL SOURCES IN DRINKING WATER

TURBIDITY
Unﬁ ltered Hetch Hetchy Water NTU 5 N/A 0.2 - 0.4 (1) [3.3] Soil runoff Filtered Water from Sunol Valley
Water Treatment Plant (SVWTP)
NTU
-
1 (2)
Min 95% of
samples
≤0.3 NTU (2)
N/A
N/A
-

99.8% - 100%
[0.4]
-
Soil runoff
Soil runoff
Filtered Water from Harry Tracy
Water Treatment Plant (HTWTP)
NTU
-
1 (2)
Min 95% of
samples
≤0.3 NTU (2)
N/A
N/A
-
100%
[0.2]
-
Soil runoff
Soil runoff

DISINFECTION BY-PRODUCTS AND PRECURSOR
Total Trihalomethanes ppb 80 N/A 9.4 - 4.7 [36]
(3) By-product of drinking water disinfection
Five Haloacetic Acids ppb 60 N/A 5.1 - 42 [28] (3) By-product of drinking water disinfection Bromate ppb 10 0.1 ND - 1.9 [2.1] (4) By-product of drinking water disinfection Total Organic Carbon (5) ppm TT N/A 1.2 - 2.2 1.8 Various natural and man-made sources

MICROBIOLOGICAL
Total Coliform (6) - NoP ≤5.0% of
monthly samples (0) - [0.0%] Naturally present in the environment Fecal coliform and E. coli (6) - 0 Positive Sample (0) - [0] Human or animal fecal waste Giardia lamblia cyst/L TT (0) 0 - 0.04 0.01 Naturally present in the environment

INORGANICS
Fluoride (source water) (7) ppm 2.0 1 ND - 0.8 0.4 (8) Erosion of natural deposits; water additive to promote strong teeth Chloramine (as chlorine) ppm MRDL = 4.0 MRDLG = 4 <0.1 - 3.8 [2.6] (4) Drinking water disinfectant added for treatment

CONSTITUENTS WITH

SECONDARY STANDARDS UNIT SMCL PHG RANGE AVERAGE TYPICAL SOURCES IN DRINKING WATER Chloride ppm 500 N/A <3 - 11 6.7 Runoff / leaching from natural deposits Speciﬁ c Conductance µS/cm 1600 N/A 34 - 217 135 Substances that form ions when in water Sulfate ppm 500 N/A 1.1 - 29 13 Runoff / leaching from natural deposits Total Dissolved Solids ppm 1000 N/A <20 - 96 52 Runoff / leaching from natural deposits Turbidity NTU 5 N/A ND - 0.2 ND Soil runoff
LEAD AND COPPER (9) UNIT AL PHG RANGE 90TH

PERCENTILE TYPICAL SOURCES IN DRINKING WATER
Copper ppb 1300 300 ND - 383 60 Internal corrosion of household water plumbing systems Lead ppb 15 0.2 ND - 190 7.1 Internal corrosion of household water plumbing systems

NON-REGULATED WATER

QUALITY PARAMETERS

UNIT ORL RANGE AVERAGE KEY
Alkalinity (as CaCO3) ppm N/A 4.5 - 79 37 < / ≤ = less than / less than or equal to AL = Action Level
Max = Maximum
Min = Minimum
N/A = Not Available
ND = Non-Detect
NL = Notiﬁ cation Level
NoP = Number of Coliform-Positive Sample
NTU = Nephelometric Turbidity Unit
ORL = Other Regulatory Level
ppb = part per billion
ppm = part per million
µS/cm = microSiemens/centimeter
Boron ppb 1000 (NL) ND - 123 ND
Calcium (as Ca) ppm N/A 3 - 17 9.5
Chlorate (10) ppb 800 (NL) 28 - 420 162
Hardness (as CaCO3) ppm N/A 7.7 - 60 34
Magnesium ppm N/A <0.2 - 5.5 2.9
pH - N/A 7.9 - 9.7 9.2
Phosphate (ortho) ppm N/A <0.3 - 0.3 <0.3
Potassium ppm N/A 0.4 - 1.1 0.7
Silica ppm N/A 3 - 5.9 4.8
Sodium ppm N/A 3.1 - 17 12
Strontium ppb N/A 14 - 181 83
San Francisco Local Groundwater - Water Quality Data for Year 2021 FOOTNOTES ON SAN FRANCISCO WATER SYSTEM - WATER QUALITY DATA:
(1) These are monthly average turbidity values measured every 4 hours daily. (2) This is a TT requirement for ﬁ ltration systems. (3) This is the highest locational running annual average value. (4) This is the highest running annual average value. (5) Total organic carbon is a precursor for disinfection byproduct formation.

The TT requirement applies to the ﬁ ltered water from the SVWTP only. (6) The MCL was changed to E. coli based starting on July 1, 2021 after the SWRCB adopted the Revised Total Coliform Rule. (7) The SWRCB recommended an optimal ﬂ uoride level of 0.7 ppm be maintained in the treated water. In 2021, the range and average of the ﬂ uoride levels were 0.6 ppm - 0.9 ppm and 0.7 ppm, respectively. (8) Natural ﬂ uoride in the Hetch Hetchy source was ND. Elevated ﬂ uoride levels in the raw water at the SVWTP and HTWTP were attributed to the transfer of ﬂ uoridated Hetch Hetchy water into the local reservoirs. (9) The most recent Lead and Copper Rule monitoring from consumer taps was in August 2021. Three of the 72 site samples collected at consumer taps had lead concentrations above the AL. (10) The detected chlorate in the treated water is a degradation product of sodium hypochlorite, which the SFRWS uses for water disinfection.

Treated Water
(Sunset
Reservoir)

DETECTED CONTAMINANTS UNIT MCL
PHG
OR
(MCLG)

RANGE AVERAGE TYPICAL SOURCES IN DRINKING WATER

INORGANICS
Chromium (VI) ppb N/A (1) 0.02 ND - 1 ND Leaching from natural deposits; waste discharges from electroplating
Nitrate (as nitrogen) ppm 10 10 ND - 0.4 ND Landscape fertilizers and leaked wastewater Fluoride ppm 2.0
(Natural-Source)
1 0.6 - 0.8 0.7 Erosion of natural deposits; water additive to promote strong teeth

CONSTITUENTS WITH

SECONDARY STANDARDS UNIT SMCL PHG
RANGE

OR LEVEL
FOUND

AVERAGE TYPICAL SOURCES IN DRINKING WATER
Chloride ppm 500 N/A 4.5 -14 7.2 Runoff / leaching from natural deposits Speciﬁ c Conductance µS/cm 1600 N/A 59 - 221 95 Substances that form ions when in water Sulfate ppm 500 N/A 4.3 4.3 Runoff / leaching from natural deposits Total Dissolved Solids ppm 1000 N/A 41 41 Runoff / leaching from natural deposits Turbidity NTU 5 N/A ND - 0.4 0.2 Soil runoff
Raw Water
(San Francisco
Local
Groundwater
Wells)

DETECTED CONTAMINANTS UNIT MCL
PHG
OR
(MCLG)

RANGE AVERAGE TYPICAL SOURCES IN DRINKING WATER
INORGANICS (2)
Chromium (VI) ppb N/A (1) 0.02 6.7 - 23 15 Leaching from natural deposits; waste discharges from electroplating
Chromium ppb 50 (100) ND - 23 11 Erosion of natural deposits; discharge from electroplating
Nitrate (as nitrogen) ppm 10 10 3.1 - 8.2 5.7 Landscape fertilizers and leaked wastewater

VOLATILE ORGANICS
Carbon tetrachloride
(3) ppb 0.5 0.1 0.6 - 0.9 0.7 Discharge from chemical plants and other industrial activities
Tetrachloroethylene (4) ppb 5 0.06 1.8 - 2.2 2 Discharge from factories, dry cleaners, and auto shops (metal degreaser)

NON-REGULATED WATER

QUALITY PARAMETERS UNIT ORL

RANGE AVERAGE
pH - N/A 7.6 - 8.4 7.9
Strontium ppb N/A 127 - 185 156
FOOTNOTES ON SAN FRANCISCO LOCAL GROUNDWATER - WATER QUALITY DATA:
(1) Chromium (VI) is currently regulated by the SWRCB under a MCL of 50 ppb for total chromium. (2) These contaminants are detectable in the raw groundwater. Blending of groundwater with surface water has been approved by SWRCB as treatment for these contaminants. In 2021, only two wells (Lake Merced Well and West Sunset Well) delivered groundwater to the distribution system intermittently. (3) This contaminant was detected at South Sunset Well and West Sunset Well but not in the blend water at Sunset Reservoir. South Sunset Well was not in operation in 2021. (4) Tetrachloroethylene was detected at Golden Gate Central Well, which supplied to Golden Gate Park throughout 2021 for irrigation only.

P.O. Box 7369
San Francisco, CA 94120-7369
San Francisco Public Utilities Commission
Every day we deliver high-quality drinking water to 2.7 million people in San Francisco, Alameda, Santa Clara and San Mateo counties. We generate clean, reliable hydroelectricity that powers 100% of San Francisco’s vital services, including police and ﬁ re stations, street lights, Muni, SF General Hospital and more.

Water quality policies are
decided at SFPUC Commission
hearings, held the 2nd and
4th Tuesdays of each month
at 1:30 pm in San Francisco
City Hall, Room 400.

This report contains important information about your drinking water. Translate it, or speak with someone who understands it.

Este informe contiene información muy importante sobre su agua potable. Tradúzcalo o hable con alguien que lo entienda bien.

Mahalaga ang impormasyong ito. Mangyaring ipasalin ito.

Cé rapport contient des information importantes concernant votre eau potable. Veuillez traduire, ou parlez avec quelqu’ un qui peut le comprendre.

Этот отчет содержит важную информацию о вашей питьевой воды. Переведите его или поговорите с тем, кто это понимает.
㘤ɻ ੥ፙଞਓҝ㟬຋ᩄ࿨ղ㘸ਗ਼ુɻ
この報告書には上水道に関する重要な情報が記されております。翻訳を御依頼なされ
るか、内容をご理解なさっておられる方にお尋ね下さい。
This report contains important information about our drinking water. Please contact SFPUC Communications at 628-215-0940 or email [email protected] for assistance.

Este informe contiene información muy importante sobre su agua potable. Favor de comunicarse con JP Streeter en tel
628-215-0940 o [email protected] para asistencia.
此報告有重要飲水資訊。需要協助，請聯絡三藩市水利局公關部，
電話:628-215-0940或電郵 [email protected]
Follow Us @MySFPUC
Anson Moran, PRESIDENT
Newsha K. Ajami, VICE PRESIDENT
Sophie Maxwell, COMMISSIONER
Tim Paulson, COMMISSIONER

CleanPowerSF Sfpuc CommissionJune 28, 2022

CleanPowerSF Sfpuc Commission
June 28, 2022