*Contact information is available on the last page of this report.
WATER RESOURCES DIVISION
ANNUAL
WATER QUALITY
REPORT
JUNE 2025
REPORTING PERIOD JAN-DEC 2024
TO DOWNLOAD THIS REPORT VISIT
SANTAMONICA.GOV/TOPIC-EXPLAINERS/YOUR-GUIDE-TO-WATER
*Contact information is available on the last page of this report. *Contact information is available on the last page of this report.
Dear Community Members,
On behalf of the City of Santa Monica, we are pleased to publish the 2025 Annual Drinking Water Quality Report to provide a summary of water quality data for the 2024 calendar year.
Throughout the year, Santa Monica Water continued to meet and exceeded all federal and state drinking water standards established by the United States Environmental Protection Agency and the State Water Resources Control Board, Division of Drinking Water (DDW).
The City’s Water Resources Division is committed to delivering safe, high quality, and sustainably sourced drinking water to the community. Earlier this year, the Los Angeles region faced severe challenges due to devastating wildfires that approached the borders of our City. Our team responded by providing critical support and resources to neighboring communities, all while maintaining the integrity and safety of our own water system.
Throughout the emergency, the Water Resources Division
worked tirelessly to manage our water storage reservoirs, leverage our diverse water supply sources to maintain peak water production capacity, and increase water quality testing efforts to ensure uninterrupted access to clean, reliable drinking water for Santa Monica residents.
While the City’s Water Resources Division continues to advance sustainable water management practices to provide a reliable and resilient water supply to the community, achieving our longterm sustainability goals are not possible without the support of our community. Continued success in water use efficiency and water conservation relies on active community participation in rebate programs, adhering to outdoor water use restrictions, and mindful water use in our everyday lives. To enhance water use efficiency, the City recently completed its Advanced Metering Infrastructure Project that provides customers with real time information about their water use, billing, and leak detection.
Please visit www.santamonica.gov/advanced-meteringinfrastructure-project for details on the project and how to sign-up for EyeOnWater to monitor your water usage and to alert you of possible water leaks on your property.
The City continues to invest in our water infrastructure through rehabilitation and replacement of aging infrastructure, implementing cutting-edge treatment technologies to protect water quality, and diversifying our water supply sources, all culminating in a resilient and sustainable water supply portfolio for the community.
On behalf of the City of Santa Monica Public Works Department and the employees of the Water Resources Division, thank you for allowing us to serve you.
Sincerely,
Sunny Wang
Water Resources Manager
Santa Monica’s Water Source
And Treatment System
The Arcadia Water Treatment Plant was recently retrofitted to enhance overall production efficiency and aid in sustainable groundwater management.
The City of Santa Monica currently obtains up to 75% of its water from local groundwater wells within the City and in West Los Angeles. The City extracts its water from three sub-basins within the Santa Monica Basin (Charnock, Olympic, and
Arcadia Sub-basins), with the Charnock Sub-basin being a local supply for over 100 years!
The treated water from the Charnock Well Field is then sent to the Arcadia Treatment Plant, and along the way it blends with water from the Olympic and Arcadia Sub-basin wells. Once the water arrives at the Arcadia Treatment Plant, it undergoes a treatment process that includes Iron/Manganese removal, filtration, Reverse Osmosis (RO) softening, disinfection, and fluoridation.
Softening is the process of removing scale-forming calcium and magnesium from hard water. RO performs softening by forcing hard water through membranes with very small pores, sized from 0.0001 - 0.001 micrometers.
TO PUT THESE UNITS INTO CONTEXT:
One part per billion (ppb) = 1 second in 31.7 years
= 1 teaspoon in 1.3 million gallons
One part per million (ppm) = 1 second in 11.6 days
= 1 teaspoon in 1,302 gallons
The complete treatment process is further outlined on the “Santa Monica Water Treatment Process” diagram.
The City of Santa Monica Water Resources Division values transparency, we hope that you find this report clear and easy to understand. If you have any questions, please call us at (310) 434-2672.
El Departamento de Recursos de Agua de la ciudad de Santa Monica valora una gestión transparente; por consiguiente, esperamos que encuentre este informe claro y fácil de
entender. Si usted tiene alguna pregunta, por favor
comuníquese al (310) 434-2672.
*Contact information is available on the last page of this report. *Contact information is available on the last page of this report.
SANTA MONICA WATER TREATMENT PROCESS
Charnock Well Field
Charnock Wells
Groundwater contaminated
with the gasoline additive
MTBE is pumped
up from 400 feet below
ground surface.
Greens and Filtration
The well water is
filtered through greensand
media to remove iron and
manganese which would
foul the
carbon filters.
GAC Filtration
The MTBE is removed by
filtering through
Granular Activated
Carbon (GAC) filters.
Pump to Treatment
Plant
The filtered water is
combined with the flow of
other wells and pumped to
the Santa Monica Water
Treatment Plant.
Santa Monica
Water Treatment
Plant
Pretreatment
To protect the sensitive Reverse Osmosis (RO) filters, the combined well flow is filtered again through greensand and cartridge filters to remove more iron, manganese and any remaining sediment.
REVERSE
OSMOSIS
FILTRATION
Reverse Osmosis Filtration
Filtration through a three-stage Reverse Osmosis
(RO) membrane system softens the water by removing
minerals (calcium and magnesium). RO uses pressure to
Water Quality force water through membranes with pores so small the Adjustments minerals can’t pass through.
The mineral content is adjusted to
the desired softness. The pH is
adjusted, fluoride is added and
the water undergoes final Storage disinfection with chloramine. The final step is to provide adequate contact time with the disinfectant in
the 5-million-gallon Arcadia Reservoir
to ensure safe drinking water.
Final Delivery
Santa Monica residents and businesses
receive water for everyday use. Water
conservation by end users is key to ensuring
water reliability and sustainability.
*Contact information is available on the last page of this report. *Contact information is available on the last page of this report.
The California Aqueduct in the Central Valley.
The remaining 25% of Santa Monica’s drinking water is
purchased from Metropolitan Water District (MWD). Treated MWD water is blended with our locally produced water, and then distributed to our residents. MWD imports water from two separate sources. One is the Colorado River water, which is delivered from Lake Havasu through a 242-mile-long aqueduct and originates as snowmelt from mountainous regions in Utah, Wyoming, and Colorado. The second is from the State Water Project, which is delivered through the 441-mile-long California Aqueduct and originates in the Sacramento-San Joaquin Delta.
MWD water is filtered at their treatment plants and undergoes extensive treatment before entering Santa Monica’s water system.
For more information about the City’s treatment facilities please call the Water Resources Division (see back cover for contact information).
Background on
Drinking Water Contaminants
The sources of drinking water (both tap water and bottled water) include rivers, lakes, 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. Contaminants that may be present in source water include:
• 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 that 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 that can be naturally occurring or be the result of oil and gas production and mining activities.
In order to ensure that tap water is safe to drink, the U.S.
Environmental Protection Agency (USEPA) and the California State Water Resources Control Board (SWRCB) prescribe
regulations that limit the concentration of certain contaminants in water provided by public water systems. SWRCB
regulations also establish limits for contaminants in bottled water that provide the same protection for public health.
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. More information about contaminants and potential health effects can be obtained by calling the USEPA’s Safe Drinking Water Hotline (1-800-426-4791).
Some people may be more vulnerable to contaminants
in drinking water than the general population. Immunocompromised persons such as persons 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 of infections. These people should seek advice about drinking water from their health care providers. USEPA/Centers for Disease Control (CDC)
guidelines on appropriate means to lessen the risk of
infection from Cryptosporidium and other microbial
contaminants are available from the Safe Drinking Water Hotline (1-800-426-4791).
** You can help protect source water purity by controlling what enters storm drains. The following site provide guides on how you can protect Drinking Water Sources:
www.epa.gov/sourcewaterprotection/easy-things-
you-can-do-protect-drinking-water-sources
Information on environmentally friendly products is available at:
https://www.santamonica.gov/departments/public-works/
office-of-sustainability-and-the-environment
To report storm drain pollution, please contact the City’s Wastewater Department. See back cover for contact information.
Source Water
Vulnerability Assessments
Between 2000 and 2012, the California State Water
Resources Control Board, Division of Drinking Water (DDW) completed Source Water Vulnerability Assessments for all the City’s groundwater wells. The assessments are required for all water utilities nationwide to evaluate the vulnerability of *Contact information is available on the last page of this report. *Contact information is available on the last page of this report.
drinking water sources for “possible contaminating activities.” Vulnerabilities most associated with contamination include commercial, industrial, urban runoff, and municipal activities.
Based on the vulnerability assessments, Santa Monica
Well #4 located mid-city, Arcadia Wells #4 and #5, and
Charnock Wells #13, #16, #18, #19 and #20, located in West L.A. are considered most vulnerable to commercial, industrial, residential, and municipal activities. Santa Monica Well #1, located on the north side of the city, Well #4, and the Arcadia Wells are considered most vulnerable by their proximity to sewer collection systems, although monthly analyses have detected no related contamination.
For more information, please contact the Water Resources Division.*
In March and June 2012, MWD completed a source water
assessment of its Colorado and State Project supplies. Based upon the vulnerability assessments, the Colorado River and State Project supplies are most vulnerable to contamination resulting from recreation, urban/storm water runoff, increasing urbanization in the watershed, and wastewater.
A copy of the assessment can be obtained by contacting
MWD (see back cover for contact information).
Santa Monica’s
Drinking Water Quality
Permission and oversight to operate a community water
system is granted annually by the DDW and the USEPA. Santa Monica’s water supply undergoes constant field and laboratory testing to ensure the highest water quality before reaching your tap. The water is sampled and analyzed daily, weekly, monthly, quarterly, semi-annually, annually, and triennially. In addition, our water quality management practice includes ensuring optimum performance of all assets associated with water production and distribution. This includes the source wells, treatment plants, distribution system, and reservoirs. Managing reservoirs to meet varying demand and testing the water at over 100 locations throughout the City’s distribution system monthly are just two examples of how water quality goals are maintained.
We look for more than 100 substances including
microorganisms, pesticides, herbicides, asbestos, lead, copper, petroleum-based products, and by-products of industrial and water treatment processes. As a result, we conduct more than 8,000 laboratory tests each year.
Our state-certified laboratory perform routine tests to ensure clean and healthy drinking water.
Water Quality Data Tables
Santa Monica Water continues to meet and exceed all USEPA and State Drinking Water Health Standards. The following data tables compare our water quality with Drinking Water Health Standards. The data is organized by source of water in two categories, each with two sub-parts:
LOCAL GROUNDWATER
— Arcadia Treatment Plant: Collects water from 9 wells, completes treatment, and sends to distribution.
— Santa Monica Well #1: Treats supply at the source and pumps directly into distribution.
METROPOLITAN WATER DISTRICT (MWD)
Treatment plants that send treated water to Santa Monica:
— Weymouth Plant
— Jensen Plant
The results are presented in two tables: Primary Drinking Water Quality Results and Secondary Drinking Water Quality Results. The primary results cover contaminants that may affect the public’s health. These contaminants include
hazardous chemicals, metals, bacteria, and radioactivity.
The secondary results cover parameters that may affect the aesthetics of the water, such as taste, appearance, and odor.
These parameters include turbidity, minerals, and pH among others.
For questions regarding water quality, call the Water
Resources Division (see back cover for contact information). *Contact information is available on the last page of this report.
PRIMARY DRINKING WATER STANDARDS (MANDATORY HEALTH-RELATED STANDARDS)
CITY OF SANTA MONICA WATER RESOURCES DIVISION
SUMMARY OF RESULTS FOR PRIMARY DRINKING WATER STANDARDS FOR 2024 LOCAL IMPORTED IMPORTED Dates Meets MAJOR SOURCES
PHG/ State WELL WATER SM WELL #1(a) SURFACE WATER SURFACE WATER Sampled Std IN DRINKING WATER PARAMETER [MCLG]/ MCL/ Arcadia Plant Jensen Plant Weymouth Plant if other {MRDLG} {MRDL} Average Range Average Range Average Range Average Range than 2024(b) Clarity
Maximum Turbidity (NTU) NS 95% < 0.3 NA NA NA NA ND 100% ≤ 0.3 ND 100% ≤ 0.3 Y Soil runoff Microbiological
Total Coliform Bacteria [0] 5% Citywide Highest Monthly: 0% Positive Samples Range: ND No violations Y Naturally present in the environment (% positive samples/month)
Fecal Coliform/E. Coli [0] (c) Citywide Maximum: 0 Positive Samples Y Human and animal fecal waste Organic Chemical
Methyl tert-Butyl Ether (MTBE) (ppb) 13 13(5*) ND ND ND ND ND ND ND ND Y Leaking underground storage tanks Trichloroethylene (ppb) 1.7 5 0.7 0.5 - 0.9 ND*** ND*** ND ND ND ND 2023*** Y Discharge from metal degreasing sites 1,2,3-Trichloropropane (TCP) (ng/L) 0.7 5 ND ND ND*** ND*** ND ND ND ND 2021*** Y Discharge and leaching from industrial/agricultural, and hazardous waste sites used as cleaning solvent for paint, varnish, and degreasing; pesticide by product Disinfection
Byproducts & Residuals
Total Trihalomethanes (ppb) NS 80 Citywide LRAA: 20.9 Range: 6.9 - 50.2 Citywide LRAA: 3.8 Range: ND - 17.5
Citywide Average: 2.00 Range: ND - 3.5
Y By-product of drinking water chlorination
Haloacetic Acids (ppb) NS 60 Y By-product of drinking water chlorination Total Chlorine/Chloramines (ppm) {4} {4} Y Drinking water disinfectant added for treatment Bromate (ppb) 0.1 10 NA NA NA NA 3.1** ND - 5.4 2.0** ND - 9.2 Y By-product of drinking water ozonation Total Organic Carbon (ppm) N/A TT NA NA NA NA 2.4** 2.0 - 2.5 2.4** 2.1 - 2.6 Inorganic Chemicals
Aluminum (ppb) 600 1000 (200*) ND ND ND*** ND*** 62** 52 - 91 93** ND - 150 2022*** Y Erosion of natural deposits; used in water treatment process Arsenic (ppb) 0.004 10 ND ND ND*** ND*** ND ND ND ND 2022*** Y Erosion of natural deposits Barium (ppm) 2 1 ND ND 0.04*** 0.04*** ND ND 124 124 2022*** Y Discharge from oil and metal industries; Erosion of natural deposits Chromium (ppb) [100] 50 ND ND ND*** ND*** ND ND ND ND 2022*** Y Discharge from steel and pulp mills; natural deposits erosion Chromium 6 (ppb) 0.02 NS 0.1 0.1 1.7*** 1.7*** ND ND ND ND 2022*** Y Naturally occuring; industrial waste discharge Copper (d) (ppm) 0.3 AL=1.3 (1.0*) Citywide, 90th percentile: 0.20 0 sites out of 35 exceeded the AL 2022 Y Corrosion of household plumbing systems Fluoride After Treatment (ppm) 1 2 Y Water additive for dental health Lead (d) (ppb) 0.2 AL=15 Citywide, 90th percentile: 2.10 0 sites out of 35 exceeded the AL (d) 2022 Y Corrosion of household plumbing systems Nitrate (as N) (ppm) 10 10 0.2 ND - 0.2 2.8 2.8 0.5 0.5 ND ND Control Range: 0.6 - 1.2 Citywide Range: 0.7 - 1.9
Runoff from fertilizer use; leaching from sewage; erosion of natural deposits Perchlorate (ppb) 1 6 ND ND 0.7*** 0.7*** ND ND ND ND 2022*** Y Industrial waste discharge Radionuclides
Alpha emitters (pCi/L) [0] 15 ND ND ND*** ND*** ND ND ND ND 2022*** Y Erosion of natural deposits Beta/photon emitters (pCi/L) [0] 50 NA NA NA NA ND ND ND ND - 5 Y Decay of natural and man-made deposits Combined Radium (pCi/L) [0] 5 ND ND ND*** ND*** ND ND ND ND 2023*** Y Erosion of natural deposits Uranium (pCi/L) 0.43 20 1.6 1.1 -2.1 ND*** ND*** 2 2 - 3 ND ND - 3 2022*** Y Erosion of natural deposits KEY TO ABBREVIATIONS FOR ADDITIONAL WATER QUALITY QUESTIONS CONTACT THE LEAD CHEMIST, CLEMENT DO, AT (310) 434-2672. PDWS = Primary Drinking Water Standards are MCLs, U.S. Environmental Protection Agency. microbial contaminants. ND = Monitored for but Not Detected *** = Santa Monica Well #1 offline in 2023 for maintenance (c) = The E. coli MCL is based on routine and repeat samples MRDLs, and Treatment Techniques TTs for contaminants MCL = Maximum Contaminant Level is the highest level of MRDL = Maximum Residual Disinfectant Level is the highest level NS = No Standard purposes. For reporting purposes, this information is from testing positive for coliforms and/or E. coli or failure that affect health, along with their monitoring and a contaminant that is allowed in drinking water. Primary of a disinfectant allowed in drinking water. There is convincing NTU = Nephelometric Turbidity Units - used to measure cloudiness 2021, 2022, or 2023 (prior to offline status). to collect required repeat samples. Fecal Coliform/E. reporting requirements. MCLs are set as close to the PHGs (or MCLGs) as is evidence that addition of a disinfectant is necessary for control of drinking water. Coli constitutes an acute MCL violation. No Level 1 (a) = SM Well#1 is pumped into a transmission line, is blended PHG = Public Health Goal is the level of a contaminant economically and technologically feasible. Secondary of microbial contaminants. TT = Treatment Technique: A required process intended to reduce Assessments or MCL violations occurred for 2024. with Imported Surface Water and enters the system in drinking water below which there is no known or MCLs are set to protect the odor, taste, and appearance LRAA = Locational Running Annual Average. The running annual the level of a contaminant in drinking water. (d) = The MCL has been replaced with a treatment technique at 19th St. & Idaho Ave. expected risk to health. PHGs are set by the California of drinking water. average is based on monitoring location. ppb = parts per billion, or micrograms per liter (µg/l) requiring agencies to optimize corrosion control. Results (b) = The City is not required to test for every parameter each Environmental Protection Agency. MRDLG = Maximum Residual Disinfectant Level Goal is the AL = Regulatory Action Level is the concentration of a contaminant ppm = parts per million, or milligrams per liter (mg/l) given are from first draw, at-the-tap monitoring performed year. If indicated, data is from a previous year. MCLG = Maximum Contaminant Level Goal is the level of a level of a drinking water disinfectant below which there which, if exceeded, triggers treatment or other requirements pCi/L = picocuries per liter every three years. contaminant in drinking water below which there is no is no known or expected risk to health. MRDLGs do not that a water system must follow. * = Secondary Standard known or expected risk to health. MCLGs are set by the reflect the benefits of the use of disinfectants to control NA = Not Applicable ** = Highest Running Average (RAA) For additional water quality questions, contact lead chemist, Clement Do at (310) 434-2672. *Contact information is available on the last page of this report.
CITY OF SANTA MONICA WATER RESOURCES DIVISION
SUMMARY OF RESULTS FOR SECONDARY DRINKING WATER STANDARDS FOR 2024
PARAMETER
PHG/ State
[MCLG] MCL
LOCAL
WELL WATER SM WELL #1(a)
Arcadia Plant
Average Range Average Range
IMPORTED
SURFACE WATER
Jensen Plant
Average Range
IMPORTED
SURFACE WATER
Weymouth Plant
Average Range
SECONDARY DRINKING WATER STANDARDS (AESTHETIC STANDARDS) Chemical Parameters
Chloride (ppm)
Color (units)
Iron (ppb)
Manganese (ppb)
Odor- Threshold (units)
Specific Conductance (µmho/cm)
Sulfate (ppm)
Total Dissolved Solids (ppm)
Turbidity (NTU)
NS 500
NS 15
NS 300
NS 50
NS 3
NS 1600
NS 500
NS 1000
— 5
26.5 25 -28 112 112
<5 <5 <5 <5 - 8
18 ND - 95.5 6.8 6.8
ND ND 5.6 5.6
<1 <1 <1 <1
324 275 - 452 1346 1339 - 1353
52.2 47.7 - 57.3 257 257
182 137 - 210 947*** 947***
0.08 0.04 - 0.14 0.17 0.14 - 0.20
40 39 - 41
1 1
ND ND
ND ND
1 1
510 498 - 522
90 89 - 92
306 291 - 322
ND ND
106 96 - 116
1 1
ND ND
ND ND
ND ND
996 912 - 1080
225 200 - 250
632 573 - 690
ND ND
Dates Meets
Sampled Std MAJOR SOURCES
if other IN DRINKING WATER
than 2023(b)
Y Runoff/leaching from natural deposits; industrial wastes Y
Y
Naturally-occurring organic materials
Leaching from natural deposits; industrial wastes
Y Leaching from natural deposits
Y
Y
Naturally-occurring organic materials; chlorine
Substances that form ions when in water; seawater influence Y Runoff/leaching from natural deposits; industrial wastes 2022*** Y
Y
Runoff/leaching from natural deposits
Soil runoff
ADDITIONAL PARAMETERS KEY TO ABBREVIATIONS
PHG = Public Health Goal is 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.
MCLG = Maximum Contaminant Level Goal is the level of a contaminant in drinking water below which there is no known or expected risk to health. MCLGs are set by the U.S. Environmental Protection Agency.
MCL = Maximum Contaminant Level is 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 are set to protect the odor, taste, and appearance of drinking water.
NL = Notification Level is a health based advisory level established by Division of Drinking Water (DDW) for chemicals in drinking water that lack maximum contaminant levels, but warrants notification.
NA = Not Applicable
NS = No Standard
ND = Monitored for, but Not Detected
NTU = Nephelometric Turbidity Units - used to measure cloudiness of drinking water.
ppb = Parts per billion, or micrograms per liter (ug/l) Alkalinity (ppm) NS NS 65.9 58.7 - 80.4 337 337 98 94 - 101 118 109 - 127 Boron (ppb) NS NL=1000 200 200 220*** 220*** 170 170 140 140 Calcium (ppm) NS NS 24 20.3 - 32.9 133 133 38 38 - 39 68 59 -76 Hardness (as CaCO3) (ppm) NS NS 106 92.6 - 134 582 582 270 235 - 305 272 241 - 303 Magnesium (ppm) NS NS 8.4 8.4 65*** 65*** 14 13 - 14 26 23 - 29 pH (units) NS NS 8.4 8.2 - 8.7 7.3 7.3 - 7.4 8.3 8.2 - 8.3 8.2 8.2 Potassium (ppm) NS NS ND ND 4.1*** 4.1*** 2.6 2.6 5 4.6 - 5.4 Radon (pCi/L) NS NS ND ND 389*** 389*** ND ND ND ND
Sodium (ppm) NS NS 30 30 89*** 89*** 46 46 105 93 - 117 1, 4-Dioxane (ppb) NS NL=1 ND ND ND*** ND*** NA NA NA NA N-Nitrosodimethylamine (NDMA) (ppt) 3 NL=10 NA NA NA NA ND ND ND ND tert-Butyl Alcohol (TBA) (ppb) NS NL=12 ND ND NA NA ND ND ND ND 2022***
2022***
2022***
2022***
2022***
2022***
FOR ADDITIONAL WATER QUALITY QUESTIONS, CONTACT CLEMENT DO, LEAD CHEMIST AT (310) 434-2672 ppm = Parts per million, or milligrams per liter (mg/l) ppt = Parts per trillion, or nanograms per liter (ng/l) umho/cm = micromhos per centimeter
< = less than
*** = Santa Monica Well #1 offline in 2023 for maintenance purposes. For reporting purposes, this information is from 2021, 2022, or 2023 (prior to offline status).
(a) = SM Well#1 is pumped into a transmission line, is blended with Imported Surface Water and enters the system at 19th St. and Idaho Ave.
(b) = We are not required to test for each parameter every year.
If indicated, data is from a previous year.
(c) = MWD has developed a flavor-profile analysis method that can more accurately identify odor occurences.
*Contact information is available on the last page of this report. *Contact information is available on the last page of this report.
Operator conducting daily water quality and performance checks at the Arcadia Water Treatment Plant.
1,4-Dioxane and
Drinking Water
1,4-Dioxane is a synthetic contaminant that has leached into numerous groundwater sources in Southern California.
It is a colorless liquid solvent and solvent stabilizer used in industrial and commercial applications. 1,4-Dioxane is an unregulated contaminant, meaning it has not completed
the regulatory standard setting process to be prescribed a maximum contaminant level (MCL). However, it has a
notification level (NL) as a precautionary measure that represents a level of contamination that is not a health risk but justifies notification to the public. 1,4-Dioxane is classified as a probable carcinogen believed to cause
health effects after long-term exposure or ingestion. In 2024, the City completed the Olympic Well Field Advanced Water Treatment Facility, co-located at the Arcadia Water Treatment Plant, to remove 1,4-dioxane through Ultraviolet Light Advanced Oxidation Process (UVAOP). The UVAOP
uses UV light and hydrogen peroxide to create hydroxyl
radicals to effectively remove 1,4-dioxane and other volatile organic contaminants from our groundwater supply.
New Ultraviolet Light Advanced Oxidation Process added to remove industrial contaminants from the Olympic Well Field.
Per- and Polyfluoroalkyl
Substances (PFAS)
PFAS are a group of compounds containing carbon to
fluorine chemical bonds, one of the strongest in organic chemistry. They are manufactured and used to enhance
repellency of water, grease, and soil in consumer products; thus, they are very stable and resistant to environmental degradation. If exposed, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) are readily absorbed but not readily eliminated from the human body. According to the SWRCB potential health concerns, long-term exposure can cause harmful health effects to a developing fetus or infant; suppress the immune system; disrupt the thyroid function, increase liver weight; and can lead to cancer.
DDW has issued drinking water notification levels (NLs) and response levels (RLs) for PFAS. According to OEHHA
recommendations, these levels provide some health risk
protection in sensitive populations and demonstrate low cancer risk with 70-year lifetime exposure.
If a utility exceeds the RL(s), regulations require the water source be taken out of service, provide treatment, or notify customers.
Perfluoroalkyl and Polyfluoroalkyl Substances
PFAS Compound Notification Level Response Level
(ppt) (ppt)
Perfluorooctanoic 5.1ppt 10 ppt
Acid (PFOA)
Perfluorooctanesulfonic 6.5 ppt 40 ppt
Acid (PFOS)
Parts per trillion (ppt) = 1 second in 31,709.8 years
Apart from drinking water, PFOA and PFOS exposure can
occur from other sources: firefighting foaming/fire preventing agents; products that repel water, grease, and soil.
In April 2019, the SWRCB investigated source water wells in California most vulnerable to PFAS contamination. This included those near airports and landfills, and later those near secondary sources of PFAS activities. SWRCB did not require Santa Monica to sample its sources. However, since 2019, City staff proactively monitors and samples the City’s Drinking Water sources for PFAS and it has not been detected in our drinking water supply to date. All PFAS samples analyzed by an outside laboratory were Non-Detect (ND). Additionally, GAC and RO, both part of the City’s treatment process, are effective at removing any PFAS compounds.
*Contact information is available on the last page of this report. *Contact information is available on the last page of this report.
Chlorate in Drinking Water
Chlorate is a common disinfectant byproduct in the drinking water treatment process that often forms when sodium
hypochlorite or chlorine dioxide are used as disinfectants. The DDW established a NL for chlorate at 0.8 mg/L. Notification level compounds in California serve as health-based advisory levels for drinking water. This is not a violation of drinking water regulations as chlorate does not have an enforceable regulatory standard. Non-carcinogenic contaminants, such as chlorate, with notification levels do not currently have MCLs because their presence does not pose an immediate health threat. Through routine proactive monitoring of the City’s water quality, an exceedance of chlorate above the NL of
0.8 mg/L was detected at the City’s Riviera Reservoir at 2.4 mg/L, but below the response level of 8.0 mg/L. Out of an abundance of caution, operation staff isolated the reservoir immediately and took it out of service upon detection.
Potential health impacts of consuming high levels of
chlorate include gastrointestinal irritation, impaired thyroid function, interference with the nervous system, increased risk of anemia, and damage to liver and kidney functions.
The chlorate level detected at the Riviera Reservoir is well below levels that would trigger these health concerns. Staff determined that the source of chlorate was from the City’s bulk sodium hypochlorite (chlorine) supplier and has since switched suppliers and implemented additional quality control measures to prevent future incidents.
Lead in Plumbing
The City’s laboratory chemists closely monitor lead results to ensure healthy drinking water, and to evaluate and determine Santa Monica’s water system has achieved “optimized
corrosion control.” The next round of testing is scheduled for 2025. A pool of “high risk” homes, which were plumbed before the ban on lead in solder, have been tested every three years since 1992 and has continually indicated there is little tendency of our water to leach lead out of plumbing.
If your home plumbing contains lead, there is a limited potential for lead to leach into your water. Fortunately, the minerals in our water help to protect against pipe corrosion, greatly reducing the potential of lead entering the water.
These minerals form a film called “scale” that prevents water from coming into direct contact with home plumbing. The most common place to find lead in household plumbing is in chrome-plated brass faucets and fixtures. California enacted stricter regulations for plumbing fixtures in 2010 further reducing the potential for lead leaching from household plumbing.
If present, however, lead can cause serious health effects in people of all ages, especially pregnant people, infants (both formula-fed and breastfed), and young children. Lead in drinking water is primarily from materials and parts used in service lines and in home plumbing. The City of Santa Monica Operators Testing Fire Hydrants During the Wildfire
Emergency to Ensure Operational Readiness.
is responsible for providing high quality drinking water and removing lead pipes but cannot control the variety of materials used in the plumbing in your home. Because lead levels may vary over time, lead exposure is possible even when your tap sampling results do not detect lead at one point in time.
You can help protect yourself and your family by identifying and removing lead materials within your home plumbing
and taking steps to reduce your family’s risk. Using a
filter, certified by an American National Standards Institute accredited certifier to reduce lead, is effective in reducing lead exposures. Follow the instructions provided with the filter to ensure the filter is used properly. Use only cold water for drinking, cooking, and making baby formula. Boiling water does not remove lead from water. Before using tap water for drinking, cooking, or making baby formula, flush your pipes for several minutes. You can do this by running your tap, taking a shower, doing laundry or a load of dishes. If you have a lead service line or galvanized requiring replacement service line, you may need to flush your pipes for a longer period.
The City of Santa Monica has completed a lead service line inventory required by the U.S. EPA’s Lead and Copper Rule Revisions which has concluded that the City’s distribution system does not contain any lead. The City’s statement
regarding our lead service line inventory can be found at www.santamonica.gov/topic-explainers/water-service.
If you are concerned about lead in your water and wish to have your water tested, contact the Water Quality Office.
Information on lead in drinking water, testing methods, and steps you can take to minimize exposure is available from the Safe Drinking Water Hotline* or at
https://www.epa.gov/safewater/lead.
*Contact information is available on the last page of this report. *Contact information is available on the last page of this report.
Santa Monica Pier
At Home Filters
The decision to buy a water filter or home treatment
system is a matter of personal preference. Our water
meets or exceeds rigid state and federal health standards.
If you decide to buy a filter or system, be a smart shopper and do some homework. Any treatment device you buy
should be registered with the National Sanitation Foundation (NSF). Contact NSF toll free at (800) 673-6275 or
visit www.nsf.org.
Bottled Water
Again, the decision is yours. You may find that keeping a pitcher of tap water in your refrigerator is a low-cost, waterthrifty alternative to buying more expensive bottled water, and it’s far better for the environment. Even when the bottle is reused or recycled, the petrochemicals used in creating the bottle and the transportation of the water have
a significant impact on the environment.
Water Conservation
The City of Santa Monica has developed a sustainable
water supply and taken responsible steps to improve water conservation amid a changing climate. The City provides many programs and incentive for our customers to conserve and improve the City’s water supply for future generations. To continue meeting our water conservation goals, the City urges our residents to continue their conservation efforts because small changes make a difference. For more information and water saving tips, please visit
www.santamonica.gov/topic-explainers/water-conservation Sustainability
The City of Santa Monica offers programs and incentives for environmentally friendly measures for the community.
For more information, please call or visit the Office of Sustainability website at:
https://www.santamonica.gov/departments/public-works/
office-of-sustainability-and-the-environment
City of Santa Monica City Hall
We need you!
Public involvement is fundamental to ensuring that we are meeting our water supply demand, water quality goals,
and the highest customer service level. We welcome your feedback and invite you to get involved with the City of Santa Monica in the following ways:
• Participate in conservation events
• Attend City Council and community meetings
• Sign up for the newsletters and alerts
• Please let us know how we are doing.
For information on these opportunities, please call Water Resources and the Office of Sustainability and the
Environment. For a digital copy of this report, please visit:
https://www.santamonica.gov/departments/public-works/
office-of-sustainability-and-the-environment
Where Can I Get More Information?
City of Santa Monica Public Works and
Water Resources Division Offices:
Water Resources/Water Quality .........(310) 434-2672
24-Hour Water Emergencies ..............(310) 434-2672
Wastewater.........................................(310) 458-8532 Lead Chemist......................................(310) 434-2672 Billing Office........................................(310) 458-8224 Visit our website:
https://www.santamonica.gov/topic-explainers/your-guideto-water Santa Monica City Council Meetings:
2nd & 4th Tuesdays of each month
Council Chamber
1685 Main Street, Santa Monica
www.santamonica.gov/departments/city-clerks-office
City of Santa Monica Office of Sustainability and
the Environment ................................... (310) 458-2213 Conservation Office.............................. (310) 458-8972 https://www.santamonica.gov/departments/public-works/office-of-sustainability-and-the-environment Metropolitan Water District (MWD)
of Southern California.......................... (213) 217-6000 Toll Free............................................... (800) 354-4420 www.mwdh2o.com
California State Water Resources Control Board
Division of Drinking Water ....................(818) 551-2004 www.waterboards.ca.gov/drinking_water/
U.S. Environmental Protection Agency
Office of Ground Water & Drinking Water
Safe Drinking Water Hotline .................(800) 426-4791 www.epa.gov/safewater/dwhealth.html
water.epa.gov/drink/guide
Water Resources Division
P.O. Box 2200, 1685 Main Street
Santa Monica, CA 90406-2200
This brochure is printed with vegetable-based inks on paper made from recycled paper.
City of Santa Monica Water Resources Division
Summary of Results for Primary and Secondary Drinking Water Standards for 2024 Table 1: Summary of Results for Primary Drinking Water Standards for 2024 (Mandatory Health-Related Standards)
PARAMETER
PHG/ State
[MCLG]/ MCL/
{MRDLG} {MRDL}
LOCAL WELL WATER
Arcadia Plant
Average Range SM WELL #1 (a)
Average Range
IMPORTED SURFACE
WATER
Jensen Plant
Average Range
IMPORTED SURFACE
WATER
Weymouth Plant
Average Range
Dates
Sampled if
other than
2023(b)
MAJOR SOURCES IN DRINKING WATER
Clarity
Maximum Turbidity (NTU)
Organic Chemicals
Methyl tert-Butyl Ether (MTBE) (ppb)
NS 95% <0.3
13 13(5*)
NA NA
ND ND
NA NA
ND ND
ND 100% ≤ 0.3
ND ND
ND 100% ≤ 0.3
ND ND
Soil runoff
Leaking underground storage tanks
Trichloroethylene (ppb) 1.7 5 0.7 0.5 - 0.9 ND*** ND*** ND ND ND ND 2023*** Discharge from metal degreasing sites 1,2,3-Trichloropropane (TCP) (ng/L)
Disinfection Byproducts & Residuals
Bromate (ppb)
Total Organic Carbon (ppm)
Inorganic Chemicals
0.7 5
0.1 10
NA TT
ND ND
NA NA
NA NA
ND*** ND***
NA NA
NA NA
ND ND
3.1** ND - 5.4
2.4** 2.0 - 2.5
ND ND
2.0** ND - 9.2
2.4** 2.1 - 2.6
2021***
By-product of drinking water ozonation
Aluminum (ppb) 600 1000 (200*) ND ND ND*** ND*** 62** 52 - 91 93** ND - 150 2022*** Erosion of natural deposits; used in water treatment process Arsenic (ppb) 0.004 10 ND ND ND*** ND*** ND ND ND ND 2022*** Erosion of natural deposits Barium (ppm) 2 1 ND ND 0.04*** 0.04*** ND ND 124 124 2022*** Discharge from oil & metal industries; erosion of natural deposits Chromium (ppb) [100] 50 ND ND ND*** ND*** ND ND ND ND 2022*** Discharge from steel and pulp mills; natural deposits erosion Chromium 6 (ppb)
Nitrate (as N) (ppm)
0.02 NS
10 10
0.1 0.1
0.2 ND - 0.2
1.7*** 1.7***
2.8 2.8
ND ND
0.5 0.5
ND ND
ND ND
2022*** Naturally occuring; industrial waste discharge
Runoff from fertilizer use; leaching from sewage; erosion of natural deposits Perchlorate (ppb)
Radionuclides
1 6 ND ND 0.7*** 0.7*** ND ND ND ND 2022*** Industrial waste discharge Alpha emitters (pCi/L)
Beta/photon emitters (pCi/L)
[0] 15
[0] 50
ND ND
NA NA
ND*** ND***
NA NA
ND ND
ND ND
ND ND
ND ND - 5
2022*** Erosion of natural deposits
Decay of natural and man-made deposits
Combined Radium (pCi/L) [0] 5 ND ND ND*** ND*** ND ND ND ND 2023*** Erosion of natural deposits Uranium (pCi/L) 0.43 20 1.6 1.1 - 2.1 ND*** ND*** 2 2 - 3 ND ND - 3 2022*** Erosion of natural deposits Table 2: Summary of Results for Primary Drinking Water Standards Monitored in Distribution System for 2024 (Mandatory Health-Related Standards) PARAMETER PHG/ State
[MCLG]/ MCL/
{MRDLG} {MRDL}
CITYWIDE DISTRIBUTION SYSTEM MAJOR SOURCES IN DRINKING WATER Microbiological
Total Coliform Bacteria
(% positive samples/month)
Fecal Coliform/E. Coli
Disinfection Byproducts & Residuals
Total Trihalomethanes (ppb)
Haloacetic Acids (ppb)
Total Chlorine/Chloramines (ppm)
Inorganic Chemicals
[0] 5%
[0] (c)
NS 80
NS 60
{4} {4}
Citywide Highest Monthly: 0% Range: ND No violations
Citywide Maximum: 0 Positive Samples
Citywide LRAA: 20.9 Range: 6.9 - 50.2
Citywide LRAA: 3.8 Range: ND - 17.5
Citywide Average: 2.00 Range: ND - 3.5
Naturally present in the environment
Human and animal fecal waste
By-product of drinking water chlorination
By-product of drinking water chlorination
Drinking water disinfectant added for treatment
Copper (d) (ppm)
Fluoride After Treatment (ppm)
0.3 AL=1.3(1.0*)
1 2
Citywide 90th percentile: 0.20 0 sites out of 35 exceeded the AL Control Range: 0.6 - 1.2 Citywide Range: 0.7 - 1.9
2022 Corrosion of household plumbing systems
Water additive for dental health
Lead (d) (ppb) 0.2 AL=15 Citywide 90th percentile: 2.10 0 site out of 35 exceeded the AL (d) 2022 Corrosion of household plumbing systems
Table 3: Summary of Results for Secondary Drinking Water Standards for 2024 (Aesthetic Standards)
PARAMETER
PHG/ State
[MCLG]/ MCL/
{MRDLG} {MRDL}
LOCAL WELL
WATER Arcadia
Plant Average
Range
SM WELL #1 (a)
Average Range
IMPORTED SURFACE
WATER Jensen
Plant Average
Range
IMPORTED SURFACE
WATER
Weymouth Plant
Average Range
MAJOR SOURCES IN DRINKING WATER
Chemical Parameters
Chloride (ppm)
Color (units)
Iron (ppb)
Manganese (ppb)
Odor-Threshold (units)
Specific Conductance (umho/cm)
Sulfate (ppm)
Total Dissolved Solids (ppm)
Turbidity (NTU)
NS 500
NS 15
NS 300
NS 50
NS 3
NS 1600
NS 500
NS 1000
- 5
26.5 25 - 28
<5 <5
18 ND - 95.5
ND ND
<1 <1
324 275 - 452
52.2 47.7 - 57.3
182 137 - 210
0.08 0.04 - 0.14
112 112
<5 <5 - 8
6.8 6.8
5.6 5.6
<1 <1
1346 1339 - 1353
257 257
947*** 947***
0.17 0.14 - 0.20
40 39 - 41
1 1
ND ND
ND ND
1 1
510 498 - 522
90 89 - 92
306 291 - 322
ND ND
106 96 - 116
1 1
ND ND
ND ND
ND ND
996 912 - 1080
225 200 - 250
632 573 - 690
ND ND
2022***
Runoff/leaching from natural deposits; industrial wastes Naturally-occuring organic materials
Leaching from natural deposits; industrial wastes
Leaching from natural deposits
Naturally-occuring organic materials; chlorine
Substances that form ions when in water; seawater influence Runoff/leaching from natural deposits; industrial wastes Runoff/leaching from natural deposits
Soil runoff
Table 4: Additional Parameters of Interest
PARAMETER PHG/ State
[MCLG]/ MCL/
{MRDLG} {MRDL}
LOCAL WELL
WATER Arcadia
Plant Average
Range
SM WELL #1 (a)
Average Range
IMPORTED SURFACE
WATER Jensen
Plant Average
Range
IMPORTED SURFACE
WATER
Weymouth Plant
Average Range
Dates
Sampled if
other than
2023(b)
Alkalinity (ppm) NS NS 65.9 58.7 - 80.4 337 337 98 94 - 101 118 109 - 127 Boron (ppb) NS NL=1000 200 200 220*** 220*** 170 170 140 140 2022*** Calcium (ppm) NS NS 24 20.3 - 32.9 133 133 38 38 - 39 68 59 - 76 Hardness (as CaCO3) (ppm) NS NS 106 92.6 - 134 582 582 270 235 - 305 272 241 - 303 Magnesium (ppm) NS NS 8.4 8.4 65*** 65*** 14 13 - 14 26 23 - 29 2022*** pH (units) NS NS 8.4 8.2 - 8.7 7.3 7.3 - 7.4 8.3 8.2 - 8.3 8.2 8.2 Potassium (ppm) NS NS ND ND 4.1*** 4.1*** 2.6 2.6 5 4.6 - 5.4 2022*** Radon (pCi/L) NS NS ND ND 389*** 389*** ND ND ND ND 2022*** Sodium (ppm) NS NS 30 30 89*** 89*** 46 46 105 93 - 117 2022*** 1,4-Dioxane (ppb) NS NL=1 ND ND ND*** ND*** NA NA NA NA 2022*** N-Nitrosodimethylamine (NDMA) (ppt) 3 NL=10 NA NA NA NA ND ND ND ND tert-Butyl Alcohol (TBA) (ppb) NS NL=12 ND ND NA NA ND ND ND ND All results meet standard.