2025 Public Health
Goal Report
(covering 2022, 2023, and 2024)
Manhattan Beach
This report was put together by
Jamie Burkhard, West Basin
Municipal Water District, June 2025
CITY OF MANHATTAN BEACH
2025 TRIENNIAL PUBLIC HEALTH GOAL REPORT
Background
Provisions of the California Health and Safety Code (HSC §116470(b)) specify that water utilities with greater than 10,000 service connections prepare a special Public Health Goal Report (Report) every three years if water quality measurements have exceeded any Public Health Goal (PHG); the latest Report is due by July 1, 2022. PHGs are non‐ enforceable goals established by the California Environmental Protection Agency (Cal‐EPA) and the Office of Environmental Health Hazard Assessment (OEHAA). The regulation also requires that where OEHHA has not adopted a PHG for a constituent, the water suppliers are to use the Maximum Contaminant Level Goal (MCLG) adopted by the United States Environmental Protection Agency (U.S. EPA). Only constituents having a California primary drinking water standard, also known as a Maximum Contaminant Level (MCL), and either a PHG or MCLG are required to be addressed in the Report.
The attached table contains a list of all relevant current PHGs, MCLGs, MCLs, and Detection Limits for purposes of Reporting (DLRs).
A few constituents are routinely detected in water systems at levels us ually well below the drinking water standards for which OEHHA or U.S. EPA has not yet adopted a PHG or MCLG. As PHGs and MCLGs are updated, the City will include them in its evaluation in future Reports as applicable.
The Report addresses any contaminants that, as of December 31, 2024, hav e Primary Drink ing Water Standards (PDWS) set by California or U.S. EPA and have an equivalent PHG or a MCLG. This includes all chemical, microbiological and radiological cons tituents detected above the DLR in the City of Manhattan Beach's (City's) water supply between 2022 and 2024 at a level exc eeding any applicable PHG or MCLG, as required by the regulation. The Report includes the numerical public health risk associated with the MCL and the PHG or MCLG, the type of risk to health that could be assoc iated with each constituent, the best treatment technology av ailable that could be used to reduce the constituent level, and an estimate of the cost to install that treatment if it is appropriate and feasible.
What are Public Health Goals (PHGs)?
PHGs are set by OEHHA and are based solely on public health risk considerations. None of the practical risk‐management factors that are considered by the U.S. EPA or State Water Resources Control Board (SWRCB) Divis ion of Drinking Water (DDW) in setting MCL drink ing water standards are considered in setting the PHGs. These factors include analy tical detection capability, treatment technology available, benefits and costs. The PHGs are not enforceable and are not required to be met by any public water system. MCLGs are the federal equivalent to PHGs and likewise are non‐enforceable.
What Water Quality Data are Considered?
All water quality data collected in the City’s water system between 2022 and 2024 for purposes of determining compliance with drinking water standards was considered. This data was all summarized in our 1 2022, 2023, and 2024 Consumer Confidence Reports (CCRs) which were posted on the City’s website at https://www.manhattanbeach.gov/departments/public-works/utilities-division/water- systems/treatment/annual-water-quality-report. Copies are also available upon reques t by contacting the City’s Utilities Division at 310-802-5304.
What Guidelines are Followed for this Report?
The Association of California Water Agencies (ACWA) formed a workgroup that prepared guidelines for water utilities to use in preparing these required reports. The ACWA guidelines were used in the preparation of the City’s report. No guidance was available from state regulatory agencies.
Best Available Treatment Technology and Cost Estimates:
Both the U.S. EPA and DDW adopt what are known as BATs or Best Available Technologies, which are the best-known methods of reducing contaminant levels to the MCL. Costs can be estimated for such technologies. However, since many PHGs and all MCLGs are set muc h lower than the MCL, it is not always possible, nor feasible to determine what treatment is needed to further reduce a constituent downward to or near the PHG or MCLG, many of which are set at zero. Estimating the costs to reduce a constituent to zero is difficult because it is not possible to verify by analytical means that the level has been lowered to zero. In some cases, installing treatment to try and further reduce very low levels of one constituent may adversely affect other aspects of water quality.
What Constituents were Detected that Exceed a PHG or MCLG? Table 1 shows the constituents that were detected above the DLR that exceeded a PHG or MCLG.
Following the table, there is a discussion of the constituents found in one or more of the City’s drinking water sources at levels above the PHG, or if no PHG, above the MCLG. It should be noted that potable water is purchased to supplement the City’s groundwater. The purchased water is from Metropolitan Water District (MWD) via a wholesaler (West Basin Municipal Water District). 2 Table 1
Parameter Units MCL
PHG or
MCLG
State
DLR
Manhattan Beach MWD
Year of
Highest
Average a
Highest
Average
2022-2024
Range
Year of
Highest
Average a
Highest
Average
2022-2024
Range
Arsenic µg/L 10 0.004 2
2023 and
2024 ND ND 2022 ND ND- 2.4
Bromate µg/L 10 0.1 1 -- NS NS 2023 7.6 b ND- 15
Gross Alpha pCi/L 15 MCLG=0 3
2023 and
2024 ND ND 2023 ND ND- 5
Gross Beta pCi/L 50 MCLG=0 4 -- NS NS 2022 4 ND- 9.0
Lead µg/L 15 c 0.2 5 2022 4.4 ND- 50 2024 ND ND d
Uranium pCi/L 20 0.43 1 2024 ND ND 2023 1 ND- 3
NOTES
Any data below the State’s DLR is considered non-detect (ND). a Data represents the highest average detected during the reporting period (2022-2024). This column shows the source year of the data displayed. b Bromate compliance is determined using the Running Annual Average (RAA). RAAs are calculated as the average of all samples collected within a 12-month period per site. The highest RAA is shown in Table 1. c There is no MCL for lead; there is an Action Level (AL). Compliance is based on the 90th percentile lead result measured at customer taps. d As a wholesaler, Metropolitan has no retail customers and is not required to collect samples at consumers' taps. MWD data shown are from treatment plant effluents.
ACRONYMS
AL: Action Level
MCL: Maximum Contaminant Level
MCLG: Maximum Contaminant Level Goal
ND: Non-Detect
NL: Notification Level
NS: Not Sampled
PHG: Public Health Goal
3 Arsenic
Arsenic is a metalloi d with properties of bot h metal and nonmetal elements. It’s a natural component of Earth’s cr ust, but so me f orms o f i t a re also used in manufacturing or i ndustrial pr ocesses l ike wood preservatives, pesticides, automobile batteries, and semiconductors.
The MCL for Arsenic is 10 micrograms per liter (µg/L). California’s DLR is 2 µg/L and the PHG is 0.004 µg/L.
Any data below the State’s DLR is considered ND. The Office of Environmental Health Hazard Assessment (OEHHA) has developed a Public Health Goal for arsenic in drinking water based on its carcinogenicity. The numerical health risk at the MCL is 2.5x10 -3. This means 2.5 cancer cases per 1,000 population. The numerical health risk at the PHG is 1x10-6. This means one cancer case per 1,000,000 population.
Manhattan Beach is not required to test for arsenic on an annual basis. It is part of a list of inorganic compounds that are tested once every three years. The groundwater wells were sampled in 2023 and 2024 to satisfy the requirements, and both results were non-detect (ND) as shown in Table 1. Metropolitan Water District took samples during all three years. In 2022, a single result was detected above the DLR. The annual average was ND, but the range shows one result above the PHG at 2.4 µg/L.
The BATs for treating arsenic are activated alumina, adsorption media, coagulation/filtration, ion exchange, oxidation/filtration, or reverse osmosis.
Bromate
Bromate is a byproduct of the disinfection process and occurs when bromide in the water r eacts with the ozone disinfectant. Bromate consumed in drinking water in excess of the MCL over many years may cause an increased risk of cancer. Bromate is categorized as a haloacetic acid.
The MCL or State drinking water standard for bromate is 10 µg/L. The PHG is 0.1 µg/L. California’s DLR is 1 µg/L. OEHHA has developed a Public Health Goal for bromate in drinking water, based on its carcinogenicity. The numerical health risk at the MCL is 1x10 -4. This means one cancer cases per 10,000 population. The numerical health risk at the PHG is 1x10 -6. This means one cancer case per 1,000,000 population.
Manhattan Beach does not use ozone, therefore it is not required to test for bromate. From 2022 through 2024, purchased water from MWD used to supplement the City’s groundwater had detections of bromate.
The highest running annual average (RAA) was 7.6 µg/L in 2023, which was below the MCL (Table 1).
Because bromate is a disinfection byproduct, the BAT for bromate involves control of the ozone treatment process to reduce its production.
Gross Alpha
There are radioactive materials naturally present in the Earth’s crust. Over billions of years, these materials can change form and create decay products. During this change process, energy is released. Gross alpha radiation is one form of the released, and that is why it can be found in drinking water.
The drinking water MCL for gross alpha is 15 picoCuries per liter (pCi/L). Because gross alpha is associated with a group of radionuclides rather than a single constituent, OEHHA concluded that a PHG was not practical. Gross alpha is carcinogenic, so the MCLG set by the U .S. EPA is 0 pCi/L. California’s DLR is 3 pCi/L. The numerical health risk at the MCL is 1x10- 3. This means one cancer case per 1,000 population.
The numerical health risk at the MCLG is 0.
4 Manhattan Beach is not required to test for radionuclides on an annual basis. As shown in Table 1, t he groundwater wells were sampled in 2023 and 2024 to satisfy the requirements, and both results were ND.
Metropolitan Water District was required to sample quarterly during 2023. The average was ND, but there were detections of gross alpha above the MCLG of 0 pCi/L. Results ranged from ND to 5 pCi/L, ultimately falling below the MCL.
The BAT for removal of gross alpha is reverse osmosis (RO).
Gr
oss Beta
The radioactive materials naturally present in Earth’s crust can decay over time. Beta particles are a type of radiation released as this decay process occurs. Gross beta can be naturally-occurring, but it can also come from man-made sources.
The drinking water MCL for gross beta is 50 picoCuries per liter (pCi/L). Similar to gross alpha, gross beta is also associated with a group of radionuclides rather than a single constituent, so OEHHA did not establish a PHG. Gross beta is a carcinogen, so the MCLG set by the U.S. EPA is 0 pCi/L. California’s DLR is 4 pCi/L.
The numerical health risk at the MCL is 2 x10
-3. This means two cancer cases per 1,000 population. The numerical health risk at the MCLG is 0.
Manhattan Beach follows requirements stated in Section 64442, Title 22, California Code of Regulations and is not currently required to test for gross beta. MWD samples quarterly for Gross Beta. The highest results were from 2022. Results of the purchased water had detections of gross beta above the MCLG as shown in Table 1. Gross beta levels ranging from ND to 9.0 pCi/L were detected in the drinking water which exceed the MCLG but fall well under the MCL.
The BAT for removal of gross beta is reverse osmosis (RO) and ion exchange (IX).
Lead
Lead i
s a heavy metal that can originate from the internal corrosion of household water plumbing systems.
Lead can also potentially come from industrial manufacturer discharges . It enters drinking water primarily through the leaching of lead-containing materials in household plumbing such as lead-based solder used to join copper pipes, brass and/or chrome-plated brass faucets, lead pipe connections from homes to water mains, and brass/bronze meters and valves.
There is no MCL for lead. Instead, taps in homes that are at higher risk for lead exposure are targeted for sampling every three years. The 90th percentile value from this sampling cannot exceed the Action Level (AL) of 15 µg/L. The most recent sampling at customers taps was in 2022. Two of the thirty-three samples exceeded the AL, but the 90th percentile value was 4.4 µg/L as shown in Table 1. Lead levels from MWD’s imported water and the levels of lead in the City’s groundwater wells were all ND during the reporting period.
OEHHA has developed a Public Health Goal for bromate in drinking water, based on its developmental Neurotoxicity, cardiovascular toxicity, and carcinogenicity. The numerical health risk at the AL is 2x10-6. This means two cancer cases per 1,000,000 people. The numerical health risk at the PHG is less than 1x10 -6.
This means one cancer case per 1,000,000 population.
The BAT for lead removal is optimal corrosion control and pH adjustment. Although not classified as a BAT, it’s also important to identify and replace lead service lines. 5 Uranium
Uranium is a naturally occurring radioactive element present in the earth’s crust. Uranium is found in both groundwater and surface water due to its natural occurrence in geological formations.
The drinking water MCL for uranium is 20 picoCuries per liter (pCi/L). The PHG is 0.43 pCi/L. California’s DLR is 1 pCi/L. Any data below the State’s DLR is considered ND. OEHHA developed a PHG in drinking water based on its carcinogenicity and kidney toxicity. The numerical health risk at the MCL is 5x10-5. This means five cancer cases per 100,000 population. The numerical health risk at the PHG is 1x10-6. This means one cancer case per 1,000,000 population.
Manhattan Beach is not required to test the groundwater for radionuclides on an annual basis. Table 1 shows there was a single result from within the 2022-2024 time period, and it was ND. MWD was required to sample quarterly during 2023. The annual average was 1.0 pCi/L with a range of ND to 3 pCi/L. All results fell below the MCL, but there were detections of gross alpha above the MCLG of 0 pCi/L.
The BAT for uranium removal includes reverse osmosis (RO) , ion exchange (IX), lime softening, and coagulation/filtration.
Estimated Costs
Accurate cost estimates are difficult, if not impossible, and are highly speculative and theoretical. Levels of the constituents listed above are already below the MCLs. Furthermore, all but one of the detections above PHGs and MCLGs come from the purchased water, not the City’s groundwater. Therefore, the City’s opinion is that cost calculations are not required. It should be noted that MWD’s potable water meets all State of California, DDW and U.S. EPA drinking water standards set to protect public health.
Recommendations for Further Action
The Manhattan Beach drinking water quality meets all State of California, DDW and U.S. EPA drinking water standards set to protect public health. To further reduce the levels of the constituents identified in this report that are already significantly below the health -based MCLs established to provide safe drinking water, additional costly treatment processes would be required. The effectiveness of the treatment processes to provide any significant reductions in constituent levels at these already low values is uncertain. The health protection benefits of these further hypothetical reductions are not at all clear and may not be quantifiable.
Additionally, because the constituents are present in the purchased drinking water, actions taken by the City may have little to no effect. Therefore, no action is proposed. 6 Attachments
1. Table of Regulated Constituents with MCLs, PHGs or MCLGs
2. Health Risk Information for Public Health Goal Exceedance Reports References:
California Health & Safety Code: Section 116470
California Code of Regulations. Title 22. Section 64442 California State Water Resources Control Board. Drinking Water Section. Hexavalent Chromium https://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/Chromium6.html Office of Environmental Health Hazard Assessment: Public Health Goals https://oehha.ca.gov/water/public-health-goals-phgs
United States Environmental Protection Agency: National Primary Drinking Water Regulations https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations 7 ATTACHMENT 1
2025 Regulated Constituents for PHG Triennial Report (2022-2024) 8 Sourced from: Association of California Water Agencies (ACWA) PHG Report Guidelines Association of California Water Agencies
1PHG REPORT GUIDELINES | Attachment 1
Chemicals with MCLs in 22 CCR §64431 — Inorganic Chemicals Regulated Contaminant MCL DLR PHG Date of PHG
Aluminum 1 0 .05 0 .6 2001
Antimony 0 .006 0 .006 0 .001 2016
Arsenic 0 .010 0 .002 0 .000004 2004
Asbestos (MFL
= million fibers per liter; for fibers
>10 microns long)
7 MFL 0 .2 MFL 7 MFL 2003
Barium 1 0 .1 2 2003
Beryllium 0 .004 0 .001 0 .001 2003
Cadmium 0 .005 0 .001 0 .00004 2006
Chromium,
Total 0 .05 0 .01 withdrawn
Nov . 2001
1999
Chromium, Hexavalent 0 .01 0 .0001 0 .00002 2011
Cyanide 0 .15 0 .1 0 .15 1997
Fluoride 2 0 .1 1 1997
Mercury (inorganic) 0 .002 0 .001 0 .0012 1999 (rev2005)* Nickel 0 .1 0 .01 0 .012 2001
Nitrate
(as nitrogen, N) 10 as N 0 .4 45 as NO3
(=10 as N)
2018
Nitrite (as N) 1 as
N 0 .4 1 as N 2018
Nitrate + Nitrite
(as N) 10 as N -- 10 as N 2018
Perchlorate 0 .006 0 .004 0 .001 2015
Selenium 0 .05 0 .005 0 .03 2010
Thallium 0 .002 0 .001 0 .0001 1999 (rev2004)
*OEHHA’s review of this chemical during the year indicated (rev20XX) resulted in no change in the PHG.
MCLs, DLRs, and PHGs for Regulated Drinking Water Contaminants Last Update: November 2024
This table includes:
• California’s maximum contaminant levels (MCLs)
• Detection limits for purposes of reporting (DLRs)
• Public health goals (PHGs) from the Office of
Environmental Health Hazard Assessment (OEHHA)
• The PHGs for NDMA, PFOA and PFOS (which ar
e not yet regulated in California) are included at the bottom of this table .
• The Federal MCLs for PFOA
and PFOS are also listed at the end of this table .
Units are in milligrams per liter (mg/L), unless otherwise noted.
Association of California Water Agencies
2PHG REPORT GUIDELINES | Attachment 1
Radionuclides with MCLs in 22 CCR §64441 and §64443 — Radioactivity Units are picocuries per liter (pCi/L), unless otherwise stated; n/a = not applicable Regulated Contaminant MCL DLR PHG Date of PHG
Gross alpha particle activity - OEHHA concluded in
2003 that a PHG was not practical
15 3 none n/a
Gross beta particle activity - OEHHA concluded in
2003 that a PHG was not practical
4 mrem/yr 4 none n/a
Radium-226 -- 1 0
.05 2006
Radium-228 -- 1 0.019 2006
Radium-226 + R
adium-228 5 -- -- --
Strontium-90 8 2 0 .35 2006
Tritium 20,000 1,000 400 2006
Uranium 20 1 0 .43 2001
Chemicals with MCLs in 22 CCR §64444 — Organic Chemicals (a) Volatile Organic Chemicals (VOCs)
Regulated Contaminant MCL DLR PHG Date of PHG
Benzene 0 .001 0 .0005 0 .00015 2001
Carbon tetrachloride 0 .0005 0 .0005 0 .0001 2000
1,2-Dichlorobenzene 0 .6 0 .0005 0 .6 1997 (rev2009)
1,4-Dichlorobenzene (p-DCB) 0 .005 0 .0005 0 .006 1997 1,1-Dichloroethane (1,1-DCA) 0 .005 0 .0005 0 .003 2003 1,2-Dichloroethane (1,2-DC
A) 0 .0005 0 .0005 0 .0004 1999 (rev2005)
1,1-Dichloroethylene (1,1-DCE) 0 .006 0 .0005 0 .01 1999 Cis-1,2-Dichloroethylene 0 .006 0 .0005 0 .013 2018
Trans-1,2-Dichlor
oethylene 0 .01 0 .0005 0 .05 2018
Dichloromethane (Methylene chloride) 0 .005 0 .0005 0 .004 2000 1,2-Dichloropropane 0 .005 0 .0005 0 .0005 1999
1,3-Dichloropropene 0 .0005 0 .0005 0 .0002 1999 (rev2006) Ethylbenzene 0 .3 0 .0005 0 .3 1997
Methyl tertiary butyl ether (MTBE) 0 .013 0 .003 0 .013 1999 Monochlorobenzene 0 .07 0 .0005 0 .07 2014
Styrene 0 .1 0 .0005 0 .0005 2010
1,1,2,2-Tetr
achloroethane 0 .001 0 .0005 0 .0001 2003
Tetrachlor
oethylene (PCE) 0 .005 0 .0005 0 .00006 2001
Toluene 0 .15 0 .0005 0 .15 1999
1,2,4-Trichlorobenzene 0 .005 0 .0005 0 .005 1999
1,1,1-Trichloroethane
(1,1,1-TCA) 0 .2 0 .0005 1 2006
1,1,2-Trichlor
oethane (1,1,2-TCA) 0 .005 0 .0005 0 .0003 2006
Trichloroethylene (T
CE) 0 .005 0 .0005 0 .0017 2009
Trichlorofluoromethane
(Freon 11) 0 .15 0 .005 1 .3 2014
1,1,2-Trichloro-1,2,2-
Trifluoroethane (Freon 113) 1 .2 0 .01 4 1997 (rev2011) Vinyl chloride 0 .0005 0 .0005 0 .00005 2000
Xylenes 1 .75 0 .0005 1 .8 1997
Association of California Water Agencies
3PHG REPORT GUIDELINES | Attachment 1
(b) Non-Volatile Synthetic Organic Chemicals (SOCs)
Regulated Contaminant MCL DLR PHG Date of PHG
Alachlor 0 .002 0 .001 0 .004 1997
Atrazine 0 .001 0 .0005 0 .00015 1999
Bentazon 0 .018 0 .002 0 .2 1999 (rev2009)
Benzo(a)pyrene 0 .0002 0 .0001 0 .000007 2010
Carbofur
an 0 .018 0 .005 0 .0007 2016
Chlordane 0 .0001 0 .0001 0 .00003 1997 (rev2006)
Dalapon 0 .2 0 .01 0.79 1997 (rev2009)
1,2-Dibr
omo-3-chloropropane (DBCP) 0 .0002 0 .00001 0 .000003 2020 2,4-Dichloropheno
xyacetic acid (2,4-D) 0 .07 0 .01 0 .02 2009
Di(2-ethylhexyl) adipate 0 .4 0 .005 0 .2 2003
Di(2-ethylhexyl) phthalate (DEHP) 0 .004 0 .003 0 .012 1997 Dinoseb 0 .007 0 .002 0 .014 1997 (rev2010)
Diquat 0 .02 0 .004 0 .006 2016
Endothal 0 .1 0 .045 0.094 2014
Endrin 0 .002 0 .0001 0 .0003 2016
Ethylene dibromide (EDB) 0 .00005 0 .00002 0 .00001 2003 Glyphosate 0 .7 0 .025 0.9 2007
Heptachlor 0 .00001 0 .00001 0 .000008 1999
Heptachlor epoxide 0 .00001 0 .00001 0 .000006 1999
Hexachlorobenzene 0 .001 0 .0005 0 .00003 2003
Hexachlor
ocyclopentadiene 0 .05 0 .001 0 .002 2014
Lindane 0 .0002 0 .0002 0 .000032 1999 (rev2005)
Methoxychlor 0 .03 0 .01 0.00009 2010
Molinate 0 .02 0 .002 0 .001 2008
Oxamyl 0 .05 0 .02 0 .026 2009
Pentachlorophenol 0 .001 0 .0002 0 .0003 2009
Picloram 0 .5 0 .001 0 .166 2016
Polychlorina
ted biphenyls (PCBs) 0 .0005 0 .0005 0.00009 2007
Simazine 0 .004 0 .001 0 .004 2001
Thiobencarb 0 .07 0 .001 0 .042 2016
To
xaphene 0 .003 0 .001 0 .00003 2003
1,2,3-T
richloropropane 0 .000005 0 .000005 0 .0000007 2009
2,3,7,8-TCDD (dio
xin) 3x10–8 5x10–9 5x10–11 2010
2,4,5-TP (Silvex) 0 .05 0 .001 0 .003 2014
Copper and Lead, 22 CCR §64672.3
Values referred to as MCLs for lead and copper are not actually MCLs; instead, they are called “Action Levels” under the lead and copper rule
Regulated Contaminant MCL DLR PHG Date of PHG
Copper 1 .3 0 .05 0 .3 2008
Lead 0 .015 0 .005 0 .0002 2009
Association of California Water Agencies
4PHG REPORT GUIDELINES | Attachment 1
Chemicals with MCLs in 22 CCR §64533 — Disinfection Byproducts Regulated Contaminant MCL DLR PHG Date of PHG
Total Trihalomethanes 0 .080 -- -- --
Bromodichlor
omethane -- 0 .0010 0 .00006 2020
Bromoform -- 0 .0010 0 .0005 2020
Chloroform -- 0 .0010 0 .0004 2020
Dibromochlor
omethane -- 0 .0010 0 .0001 2020
Haloacetic Acids (five) (HAA5) 0 .060 -- -- --
Monochloroacetic Acid -- 0 .0020 -- --
Dichloroacetic Adic -- 0 .0010 -- --
Trichlor
oacetic Acid -- 0 .0010 -- --
Monobromoacetic Acid -- 0 .0010 -- --
Dibromoacetic Acid -- 0 .0010 -- --
Broma
te 0 .010 0.0050** 0 .0001 2009
Chlorite 1 .0 0 .020 0 .05 2009
**The DLR for Bromate is 0.0010 mg/L for analysis performed using EPA Method 317.0 Revision 2.0, 321.8, or 326.0.
Chemicals with PHGs established in response to DDW requests. These are not currently regulated drinking water contaminants.***
Regulated Contaminant MCL DLR PHG Date of PHG
N-Nitrosodimethylamine (NDMA) -- -- 0 .000003 2006
Perfluor
ooctanoic acid (PFOA)*** -- -- 0 .00000007 2024
Perfluor
ooctane sulfonic acid (PFOS)*** -- -- 0 .000001 2024
***PFOA and PFOS have US EPA MCLGs and MCLs.
PFOA – MCLG is zero. MCL is 4 ng/L
PFOS – MCLG is zero. MCL is 4 ng/L
ATTACHMENT 2
2025 Health Risk Information for Public Health Goal
Exceedance Reports
Sourced from: Association of California Water Agencies (ACWA) PHG Report Guidelines Association of California Water Agencies
1PHG REPORT GUIDELINES | Attachment 2
DRAFT – FOR REVIEW ONLY
OFFICE OF ENVIRONMENTAL HEALTH HAZARD ASSESSMENT
Public Health Goals
Health Risk Information
for Public Health Goal
Exceedance Reports
February 2025
Pesticide and Environmental Toxicology Branch
Office of Environmental Health Hazard Assessment
California Environmental Protection Agency
Association of California Water Agencies
2PHG REPORT GUIDELINES | Attachment 2
Health Risk Information for
Public Health Goal Exceedance Reports
Prepared by
Office of Environmental Health Hazard Assessment
California Environmental Protection Agency
February 2025
NEW for the 2025 Report: New in this document are newly established Public Health Goals(PHGs)for perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), and five haloacetic acids: monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid, and dibromoacetic acid.
Background: Under the Calderon-Sher Safe Drinking Water Act of 1996 (the Act), public water systems with more than 10,000 service connections are required toprepare a report every three years for contaminants that exceed their respective PHGs.
1 This document contains health risk information on drinking water contaminantsto assist public water systems in preparing these reports. A PHG is the concentration of a contaminant in drinking water that poses no significant health risk if consumed for a lifetime. PHGs are developed and published by the Office of Environmental Health Hazard Assessment (OEHHA) using current risk assessment principles, practices and methods.
2 The water system’s report is required to identify the health risk category (e.g., carcinogenicity or neurotoxicity) associated with exposure to each contaminant in drinking water that has a PHG and to include a brief, plainly worded description of these risks. There port is also required to disclose the numerical public health risk, if available, associated with the California Maximum Contaminant Level (MCL) and with the PHG for each contaminant. This health risk information document is prepared by OEHHA every three years to assist the water systems in providing the required information in their reports.
1 Health and Safety Code Section 116470(b)
2 Health and Safety Code Section 116365
Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2025
Association of California Water Agencies
3PHG REPORT GUIDELINES | Attachment 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-carcino- genic 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 techno- logical 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 comply- ing 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 chem- ical 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 2025
Association of California Water Agencies
4PHG REPORT GUIDELINES | Attachment 2
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)
7MFL7
(fibers>10
microns in
length)
1×10-6 7MFL
(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)
Barium cardiovascular toxicity
(causes high blood
pressure)
2 NA 1 NA
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, equivalent to 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. 1×10-6means 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.
Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2025
Association of California Water Agencies
5PHG REPORT GUIDELINES | Attachment 2
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
Bentazon hepatotoxicity and
digestive system
toxicity (harms the liver,
intestine, and causes
body weight effects8)
0.2 NA 0.018 NA
Benzene carcinogenicity
(causesleukemia)
0.00015 1×10-6 0.001 7×10-6
(seven per
million)
Benzo[a]pyrene carcinogenicity
(causescancer)
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
Carbon
tetrachloride
carcinogenicity (causes
cancer)
0.0001 1×10-6 0.0005 5×10-6
(five per
million)
8 Body weight effects are an indicator of general toxicity in animal studies.
Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2025
Association of California Water Agencies
6PHG REPORT GUIDELINES | Attachment 2
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
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 0.010 5×10-4 (five
per ten
thousand)
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
Di(2-ethylhexyl)
phthalate (DEHP)
carcinogenicity
(causes cancer)
0.012 1×10-6 0.004 3×10-7
(three per
ten million)
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).
Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2025
Association of California Water Agencies
7PHG REPORT GUIDELINES | Attachment 2
Chemical Health Risk Category1
California
PHG
(mg/L)2
Cancer
Risk3 at
the PHG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
1,2-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
Dichloromethane
(methylene chloride)
carcinogenicity
(causes cancer)
0.004 1×10-6 0.005 1×10-6
(one per
million)
Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2025
Association of California Water Agencies
8PHG REPORT GUIDELINES | Attachment 2
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
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
Ethylene dibromide
(1,2-Dibromoethane)
carcinogenicity
(causes cancer)
0.00001 1×10-6 0.00005 5×10-6
(five per
million)
Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2025
Association of California Water Agencies
9PHG REPORT GUIDELINES | Attachment 2
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
Fluoride musculoskeletal toxicity
(causes tooth mottling)
1 NA 2 NA
Glyphosate nephrotoxicity
(harms the kidney)
0.9 NA 0.7 NA
Haloaceticacids:
dibromoacetic acid
carcinogenicity
(causes cancer)
0.00003 1×10-6 0.06* 2×10-3
(two per
thousand)10
Haloaceticacids:
dichloroacetic acid
carcinogenicity
(causes cancer)
0.0002 1×10
-6 0.06* 3×10-4
(three per
ten
thousand)11
Haloaceticacids
:monobromo-
acetic acid
musculoskeletal toxicity
(causes muscular
degeneration)
0.025 NA 0.06* NA
Haloaceticacids
:monochloro-
acetic acid
general toxicity (causes
body and organ
weightchanges
8)
0.053 NA 0.06* NA
Haloaceticacids:
trichloroacetic acid
carcinogenicity
(causes cancer)
0.0001 1×10
-6 0.06* 6×10-4
(six per ten
thousand)12
Heptachlor carcinogenicity
(causes cancer)
0.000008
(8×10-6)
1×10-6 0.00001 1×10-6
(one per
million)
* For total haloacetic acids (the sum of dibromoacetic acid, dichloroaceticacid, monobromoaceticacid, monochloroacetic acid, and trichloroacetic acid).
There are no MCLs for individual haloacetic acids.
10 Basedon0.060 mg/L dibromoacetic acid; the risk will vary with different combinations and ratios of the other haloacetic acids in a particular sample.
11 Basedon0.060 mg/L dichloroacetic acid; the risk will vary with different combinations and ratios of the other haloacetic acids in a particular sample.
12 Basedon0.060 mg/L trichloroacetic acid; the risk will vary with different combinations and ratios of the other haloacetic acids in a particular sample.
Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2025
Association of California Water Agencies
10PHG REPORT GUIDELINES | Attachment 2
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
Heptachlor
epoxide
carcinogenicity
(causes cancer)
0.000006
(6×10-6)
1×10-6 0.00001 2×10-6
(two per
million)
Hexachloro-
benzene
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 neuro behavioral
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)
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
Methyltertiary-
butyl ether
(MTBE)
carcinogenicity
(causes cancer)
0.013 1×10
-6 0.013 1×10-6
(one per
million)
Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2025
Association of California Water Agencies
11PHG REPORT GUIDELINES | Attachment 2
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
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
Nitrate and
Nitrite
hematotoxicity
(causes
methemoglobinemia)
10 as
nitrogen13
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
13 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 2025
Association of California Water Agencies
12PHG REPORT GUIDELINES | Attachment 2
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
Pentachloro-phe-
nol (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
Perfluorooctane-
sulfonic acid
(PFOS)
carcinogenicity (causes
cancer)
1×10
-6 1×10-6 NA NA
Perfluoro-octanoi-
cacid (PFOA)
carcinogenicity (causes
cancer)
7×10
-9 1×10-6 NA NA
Picloram hepatotoxicity
(harms the liver)
0.166 NA 0.5 NA
Polychlorinatedbi-
phenyls (PCBs)
carcinogenicity
(causes cancer)
0.00009 1×10
-6 0.0005 6×10-6
(six per
million)
Radium-226 carcinogenicity
(causes cancer)
0.05pCi/L 1×10-6 5 pCi/L
(combined
Ra226+228)
1×10-4
(one per ten
thousand)
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
Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2025
Association of California Water Agencies
13PHG REPORT GUIDELINES | Attachment 2
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
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 8pCi/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)
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
Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2025
Association of California Water Agencies
14PHG REPORT GUIDELINES | Attachment 2
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
Thiobencarb general toxicity
(causes body weight
effects)
hematotoxicity
(affects red blood cells)
0.042 NA 0.07 NA
Toluene
(methylbenzene)
hepatotoxicity
(harms the liver)
endocrne 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
endocrine 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
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)
Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2025
Association of California Water Agencies
15PHG REPORT GUIDELINES | Attachment 2
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
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 (Freon113)
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)14
Trihalomethanes:
Bromoform
carcinogenicity
(causes cancer)
0.0005 1x10
-6 0.080# 2×10-4
(two per ten
thousand)15
Trihalomethanes:
Chloroform
carcinogenicity
(causes cancer)
0.0004 1x10 -6 0.080# 2×10-4
(two per ten
thousand)16
# For total trihalomethanes (the sum of bromodichloromethane, bromoform, chloroform, and dibromochloromethane). There are no MCLs for individual trihalomethanes. 14 Based on 0.080 mg/L bromodichloromethane; the risk will vary with different combinations and ratios of the other trihalomethanes in a particular sample.
15 Based on 0.080 mg/L bromoform; the risk will vary with different combinations and ratios of the other trihalomethanes in a particular sample.
16 Based on 0.080 mg/L chloroform; 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 2025
Association of California Water Agencies
16PHG REPORT GUIDELINES | Attachment 2
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:
Dibromochloro-
methane
carcinogenicity
(causes cancer)
0.0001 1x10
-6 0.080# 8×10-4
(eight per ten
thousand)17
Tritium carcinogenicity
(causes cancer)
400pCi/L 1x10 -6 20,000
pCi/L
5×10-5
(five per
hundred
thousand)
Uranium carcinogenicity
(causes cancer)
0.43pCi/L 1×10-6 20pCi/L 5×10-5
(five per
hundred
thousand)
Vinylchloride 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 dibromochloro- methane). There are no MCLs for individual trihalomethanes. 17 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 2025
Association of California Water Agencies
17PHG REPORT GUIDELINES | Attachment 2
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)2
Cancer
Risk3 at
the PHG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
Disinfection by products (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
Radionuclides
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.
Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2025
Association of California Water Agencies
18PHG REPORT GUIDELINES | Attachment 2
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)2
Cancer
Risk3 at
the PHG
California
MCL4
(mg/L)
Cancer
Risk at the
California
MCL
Gross alpha
particles8
carcinogenicity
(causes cancer)
0 (
210Po
included)
0 15 pCi/L 9
(includes
radium
but not
radon and
uranium)
up to 1x10-3
(for 210Po,
the most
potent alpha
emitter)
Beta particles and
photon emitters8
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)
8 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. 9 pCi/L= picocuries per liter of water.
Office of Environmental Health Hazard Assessment
Water Toxicology Section
February 2025