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EWG's Tap Water Database

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San Francisco City Water System

 

EWG's drinking water quality report shows results of tests conducted by the water utility and provided to the Environmental Working Group by the California State Water Resources Control Board, as well as information from the U.S. EPA Enforcement and Compliance History database (ECHO). For the latest quarter assessed by the EPA (July 2018 - September 2018), tap water provided by this water utility was in compliance with federal health-based drinking water standards.

This water utility buys or otherwise receives some or all of its finished water from one or more public water utility systems. EWG research suggests that this utility purchases water from a single supplier, San Francisco Regional Water System. Tap water results displayed on the utility page show the water quality testing conducted by the original water supplier and this utility.

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3

contaminants detected above health guidelines

6

other detected contaminants

    Includes chemicals detected in 2015 for which annual utility averages exceeded an EWG-selected health guideline established by a federal or state public health authority; chemicals detected under the EPA's Unregulated Contaminant Monitoring Rule (UCMR 3) program in 2013 to 2015, for which annual utility averages exceeded a health guideline established by a federal or state public health authority; radiological contaminants detected between 2010 and 2015.

  • Chromium (hexavalent)

    cancer

    Chromium (hexavalent) is a carcinogen that commonly contaminates American drinking water. Chromium (hexavalent) in drinking water may be due to industrial pollution or natural occurrences in mineral deposits and groundwater. Read more about chromium (hexavalent).

    STATE

    NATIONAL

    THIS UTILITY

    How your levels compare

    HEALTH GUIDELINE:
    0.02 ppb
    0.782 ppb
    1.69 ppb
    0.0906 ppb
    The State and National averages were calculated using the averages of the contaminant measurements for each utility in 2010-2015.
    ppb = parts per billion.

    Health risks of chromium (hexavalent) in excess of health guideline

    The health guideline of 0.02 ppb for chromium (hexavalent) was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.

    Testing summary by quarter

    NOT TESTED

    NOT DETECTED

    DETECTED

    ABOVE HEALTH GUIDELINE

    • Utility Average 2010-2015: 0.0906 ppb
    • Health Guideline Exceeded 2010-2015: Yes
    • Legal Limit Exceeded 2010-2015: No
    Utility
    Average
    2010-2015
    Health
    Guideline
    Exceeded
    2010-2015
    Legal
    Limit
    Exceeded
    2010-2015
    2010 2011 2012 2013 2014 2015
    0.0906 ppb Yes No

  • Radiological contaminants

    cancer

    This utility detected Radium, combined (-226 & -228) & Radium-228.

    Radiological contaminants leach into water from certain minerals and from mining. Drinking water contamination with radioactive substances increases the risk of cancer and may harm fetal development.

  • Total trihalomethanes (TTHMs)

    cancer

    Trihalomethanes are cancer-causing contaminants that form during water treatment with chlorine and other disinfectants. The total trihalomethanes group includes four chemicals: chloroform, bromodichloromethane, dibromochloromethane and bromoform.

    STATE

    NATIONAL

    THIS UTILITY

    How your levels compare

    HEALTH GUIDELINE:
    0.8 ppb
    23.7 ppb
    20.1 ppb
    54.0 ppb
    The State and National averages were calculated using the averages of the contaminant measurements for each utility in 2015.
    ppb = parts per billion.

    Health risks of trihalomethanes in excess of health guideline

    The health guideline of 0.8 ppb for trihalomethanes was defined by the California Office of Environmental Health Hazard Assessment as a draft public health goal, the level of drinking water contaminant that does not pose a significant health risk. This health guideline protects against cancer.

    Testing summary by quarter

    NOT TESTED

    NOT DETECTED

    DETECTED

    ABOVE HEALTH GUIDELINE

    ABOVE LEGAL LIMIT

    • Utility Average 2015: 54.0 ppb
    • Health Guideline Exceeded 2015: Yes
    • Legal Limit Exceeded 2015: No
    Utility
    Average
    2015
    Health
    Guideline
    Exceeded
    2015
    Legal
    Limit
    Exceeded
    2015
    2010 2011 2012 2013 2014 2015
    54.0 ppb Yes No

    Includes chemicals detected in 2015 for which annual utility averages were lower than an EWG-selected health guideline established by a federal or state public health authority; chemicals detected under the EPA's Unregulated Contaminant Monitoring Rule (UCMR 3) program in 2013 to 2015, for which annual utility averages were lower than an EWG-selected health guideline established by a federal or state public health authority.

  • Chlorate


    Chlorate forms in drinking water as a byproduct of disinfection. Chlorate impairs thyroid function, making chlorate exposure most harmful during pregnancy and childhood.

    STATE

    NATIONAL

    THIS UTILITY

    How your levels compare

    HEALTH GUIDELINE:
    210 ppb
    114.0 ppb
    128.7 ppb
    137.5 ppb
    The State and National averages were calculated using the averages of the contaminant measurements for each utility in 2010-2015.
    ppb = parts per billion.

    Health risks of chlorate in excess of health guideline

    The health guideline of 210 ppb for chlorate was defined by the Environmental Protection Agency as a benchmark for testing under the Unregulated Contaminant Monitoring Rule program. This health guideline protects against hormone disruption.

    Testing summary by quarter

    NOT TESTED

    NOT DETECTED

    DETECTED

    ABOVE HEALTH GUIDELINE

    • Utility Average 2010-2015: 137.5 ppb
    • Health Guideline Exceeded 2010-2015: No
    • Legal Limit Exceeded 2010-2015: No
    Utility
    Average
    2010-2015
    Health
    Guideline
    Exceeded
    2010-2015
    Legal
    Limit
    Exceeded
    2010-2015
    2010 2011 2012 2013 2014 2015
    137.5 ppb No No

  • Chromium (total)


    Chromium is a naturally occurring metal, but industrial uses can elevate its levels in water. One form, hexavalent chromium, causes cancer. Total chromium is not a good indicator of the amount of hexavalent chromium in drinking water.

    STATE

    NATIONAL

    THIS UTILITY

    How your levels compare

    0.637 ppb
    1.54 ppb
    0.0367 ppb
    The State and National averages were calculated using the averages of the contaminant measurements for each utility in 2010-2015.
    ppb = parts per billion.

    Testing summary by quarter

    NOT TESTED

    NOT DETECTED

    DETECTED

    ABOVE LEGAL LIMIT

    • Utility Average 2010-2015: 0.0367 ppb
    • Health Guideline Exceeded 2010-2015: No
    • Legal Limit Exceeded 2010-2015: No
    Utility
    Average
    2010-2015
    Health
    Guideline
    Exceeded
    2010-2015
    Legal
    Limit
    Exceeded
    2010-2015
    2010 2011 2012 2013 2014 2015
    0.0367 ppb No No

  • Fluoride


    Fluoride occurs naturally in surface and groundwater and is also added to drinking water by many water systems.

    STATE

    NATIONAL

    THIS UTILITY

    How your levels compare

    0.440 ppm
    0.350 ppm
    0.660 ppm
    The State and National averages were calculated using the averages of the contaminant measurements for each utility in 2015.
    ppm = parts per million.

    Testing summary by quarter

    NOT TESTED

    NOT DETECTED

    DETECTED

    ABOVE LEGAL LIMIT

    • Utility Average 2015: 0.660 ppm
    • Health Guideline Exceeded 2015: No
    • Legal Limit Exceeded 2015: No
    Utility
    Average
    2015
    Health
    Guideline
    Exceeded
    2015
    Legal
    Limit
    Exceeded
    2015
    2010 2011 2012 2013 2014 2015
    0.660 ppm No No

  • Haloacetic acids (HAA5)


    Haloacetic acids are formed when disinfectants such as chlorine are added to tap water. The group of five haloacetic acids regulated by federal standards includes monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid and dibromoacetic acid.

    STATE

    NATIONAL

    THIS UTILITY

    How your levels compare

    12.9 ppb
    11.0 ppb
    43.0 ppb
    The State and National averages were calculated using the averages of the contaminant measurements for each utility in 2015.
    ppb = parts per billion.

    Testing summary by quarter

    NOT TESTED

    NOT DETECTED

    DETECTED

    ABOVE LEGAL LIMIT

    • Utility Average 2015: 43.0 ppb
    • Health Guideline Exceeded 2015: No
    • Legal Limit Exceeded 2015: No
    Utility
    Average
    2015
    Health
    Guideline
    Exceeded
    2015
    Legal
    Limit
    Exceeded
    2015
    2010 2011 2012 2013 2014 2015
    43.0 ppb No No

  • Strontium


    Strontium is a metal that accumulates in the bones. Radioactive strontium-90 can cause bone cancer and leukemia, and any form of strontium at high doses can harm bone health.

    STATE

    NATIONAL

    THIS UTILITY

    How your levels compare

    HEALTH GUIDELINE:
    1,500 ppb
    357.2 ppb
    443.1 ppb
    74.3 ppb
    The State and National averages were calculated using the averages of the contaminant measurements for each utility in 2010-2015.
    ppb = parts per billion.

    Health risks of strontium in excess of health guideline

    The health guideline of 1,500 ppb for strontium was defined by the Environmental Protection Agency as a benchmark for testing under the Unregulated Contaminant Monitoring Rule program. This health guideline protects against harm to bones.

    Testing summary by quarter

    NOT TESTED

    NOT DETECTED

    DETECTED

    ABOVE HEALTH GUIDELINE

    • Utility Average 2010-2015: 74.3 ppb
    • Health Guideline Exceeded 2010-2015: No
    • Legal Limit Exceeded 2010-2015: No
    Utility
    Average
    2010-2015
    Health
    Guideline
    Exceeded
    2010-2015
    Legal
    Limit
    Exceeded
    2010-2015
    2010 2011 2012 2013 2014 2015
    74.3 ppb No No

  • Vanadium


    Vanadium is a metal used in steels and other alloys. People are commonly exposed to vanadium in water and food. Excessive exposure can be toxic during pregnancy and childhood.

    STATE

    NATIONAL

    THIS UTILITY

    How your levels compare

    HEALTH GUIDELINE:
    21 ppb
    1.98 ppb
    7.27 ppb
    0.148 ppb
    The State and National averages were calculated using the averages of the contaminant measurements for each utility in 2010-2015.
    ppb = parts per billion.

    Health risks of vanadium in excess of health guideline

    The health guideline of 21 ppb for vanadium was defined by the Environmental Protection Agency as a benchmark for testing under the Unregulated Contaminant Monitoring Rule program. This health guideline protects against change in blood chemistry.

    Testing summary by quarter

    NOT TESTED

    NOT DETECTED

    DETECTED

    ABOVE HEALTH GUIDELINE

    • Utility Average 2010-2015: 0.148 ppb
    • Health Guideline Exceeded 2010-2015: No
    • Legal Limit Exceeded 2010-2015: No
    Utility
    Average
    2010-2015
    Health
    Guideline
    Exceeded
    2010-2015
    Legal
    Limit
    Exceeded
    2010-2015
    2010 2011 2012 2013 2014 2015
    0.148 ppb No No

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Pollution sources

Click on each pollution source to see from which source contaminants come.

agriculture icon

Agriculture

teardrop 1
industry icon

Industry

teardrop 7
water treatment icon

Treatment
byproducts

tear drop 4
urban area icon

Runoff &
sprawl

teardrop 0
naturally occuring icon

Naturally
occuring

teardrop 6

  • Chlorate
  • Chlorate
  • Chromium (total)
  • Strontium
  • Chromium (hexavalent)
  • Vanadium
  • Radium, combined (-226 & -228)
  • Radium-228
  • Chromium (total)
  • Strontium
  • Chromium (hexavalent)
  • Vanadium
  • Radium, combined (-226 & -228)
  • Radium-228
    • Chlorate
    • Fluoride
    • Haloacetic acids (HAA5)
    • Total trihalomethanes (TTHMs)
    Specific water contaminants can come from more than one source.

    San Francisco City Water System compliance with legally mandated federal standards

    • From October 2015 to September 2018, San Francisco City Water System was in violation of health-based drinking water standards:
      No
    Information in this section on San Francisco City Water System comes from the U.S. EPA Enforcement and Compliance History Online database. Click here for more information for this utility.

    Other contaminants tested


    Contaminants detected between 2010 and 2014 and were not part of EPA's UCMR-3 testing program:

    Bromide

     

    Chemicals tested for but not detected from 2010 to 2015:

    1,1,1-Trichloroethane, 1,1,2,2-Tetrachloroethane, 1,1,2-Trichloroethane, 1,1-Dichloroethane, 1,1-Dichloroethylene, 1,2,3-Trichloropropane, 1,2,4-Trichlorobenzene, 1,2-Dibromo-3-chloropropane (DBCP), 1,2-Dichloroethane, 1,2-Dichloropropane, 1,3-Butadiene, 1,3-Dichloropropene, 1,4-Dioxane, 17-beta-Estradiol, 2,3,7,8-TCDD (Dioxin), 2,4,5-TP (Silvex), 2,4-D, 3-Hydroxycarbofuran, 4-Androstene-3,17-dione, Alachlor (Lasso), Aldicarb, Aldicarb sulfone, Aldicarb sulfoxide, Aldrin, Aluminum, Antimony, Arsenic, Asbestos, Atrazine, Barium, Baygon (Propoxur), Bentazon (Basagran), Benzene, Benzo[a]pyrene, Beryllium, Bromochloromethane, Bromomethane, Cadmium, Carbaryl, Carbofuran, Carbon tetrachloride, Chlordane, Chlorodifluoromethane, Chloromethane, cis-1,2-Dichloroethylene, Cobalt, Combined uranium, Cyanide, Dalapon, DCPA mono- and di-acid degradates, Di(2-ethylhexyl) adipate, Di(2-ethylhexyl) phthalate, Dicamba, Dichlorodifluoromethane, Dichloromethane (methylene chloride), Dieldrin, Dinoseb, Diquat, Endothall, Endrin, Equilin, Estriol, Estrone, Ethinyl estradiol, Ethylbenzene, Ethylene dibromide, Glyphosate, Heptachlor, Heptachlor epoxide, Hexachlorobenzene (HCB), Hexachlorocyclopentadiene, Lindane, m- & p-Xylene, Manganese, Mercury (inorganic), Methiocarb, Methomyl, Methoxychlor, Molinate, Molybdenum, Monochlorobenzene (chlorobenzene), MTBE, Nitrate, Nitrate & nitrite, Nitrite, o-Dichlorobenzene, o-Xylene, Oxamyl (Vydate), p-Dichlorobenzene, Pentachlorophenol, Perchlorate, Perfluorobutane sulfonate (PFBS), Perfluoroheptanoic acid (PFHPA), Perfluorohexane sulfonate (PFHXS), Perfluorononanoic acid (PFNA), Perfluorooctane sulfonate (PFOS), Perfluorooctanoic acid (PFOA), Picloram, Polychlorinated biphenyls (PCBs), Radium-226, Selenium, Silver, Simazine, Styrene, Testosterone, Tetrachloroethylene (perchloroethylene), Thallium, Thiobencarb, Toluene, Toxaphene, trans-1,2-Dichloroethylene, Trichloroethylene, Trichlorofluoromethane, Trichlorotrifluoroethane, Vinyl chloride, Xylenes (total)