EPA SDWIS · San Francisco County, California · 36 providers profiled
San Francisco County, CA Water Quality Report
San Francisco County is served by 36 major public water systems on file with the EPA.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
📅Updated Quarterly
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Results for San Francisco County, CA
36 water providers on file for this county, sorted by population served.
Quick answer: San Francisco County has 36 water providers profiled, sorted by population served.
Sodium
Calcium
Alkalinity, Total
Alkalinity, Bicarbonate
TDS
Chloride
Turbidity
Chlorate
Conductivity (at 25°C)
Hardness, Total (ASCACO3)
Lead Summary
Lead
Totalhaloaceticacids (HAA5)
TTHM
Chloroform
Bromodichloromethane
Dibromochloromethane
Dichloroaceticacid
Trichloroaceticacid
Monochloroaceticacid
Copper, Free
Magnesium
Foamingagents (SURFACTANTS)
Sulfate
Carbon, Total
Nitrate-Nitrite
Nitrate
Chromium, Hex
Carbontetrachloride
Tetrachloroethylene
Perchlorate
Chromium
Arsenic
Color
Alkalinity, Carbonate
PFPEA
PFBA
PFHXS
PFHPA
PFOA
PFHXA
PFBS
Bromoform
Monobromoaceticacid
Dibromoaceticacid
Aggressive Index
pH
Iron
Manganese
Methyltert-Butylether
Fluoride
Odor
Aluminum
Combined Uranium
Gross Alpha Particle Activity
Copper Summary
Contaminants found
Metals
Naturally occurring or corrosion-related elements, e.g. lead, arsenic, copper
Lead Summary
Detected: 0.1 mg/L (ppm)
Found at 6 providers
Lead
Detected: 6.7 UG/L (ppb)
7/23/2025
A metal that can leach from old pipes, solder, and fixtures. Current medical guidance holds there is no truly safe level of lead exposure, especially for children and pregnant women.
Copper, Free
Detected: 103 UG/L (ppb)
Found at 3 providers
Chromium, Hex
Detected: 16.7 UG/L (ppb)
Found at 2 providers
Chromium
Detected: 22.3 UG/L (ppb)
Found at 2 providers
Occurs in two forms — trivalent (an essential nutrient in trace amounts) and hexavalent (linked to increased cancer risk).
Arsenic
Detected: 2.14 UG/L (ppb)
Found at 3 providers
Occurs naturally in some groundwater. Long-term exposure above the legal limit (10 ppb) has been linked to increased cancer risk and cardiovascular disease.
Iron
Detected: 2380 UG/L (ppb)
Found at 2 providers
Mostly an aesthetic issue (metallic taste, staining) rather than a health concern at typical levels.
Manganese
Detected: 403 UG/L (ppb)
Found at 2 providers
Mainly a taste/staining concern at typical levels; long-term neurological research at high chronic exposure is ongoing.
Aluminum
Detected: 63.4 UG/L (ppb)
6/30/2025
Combined Uranium
Detected: 2.6 PCI/L
4/9/2025
A naturally occurring radioactive metal. Long-term exposure above the legal limit is associated with kidney effects and increased cancer risk.
Copper Summary
Detected: 1.602 mg/L (ppm)
12/31/2003
Disinfection Byproducts
Formed when chlorine used to disinfect water reacts with organic matter
Totalhaloaceticacids (HAA5)
Detected: 54.5 UG/L (ppb)
Found at 6 providers
TTHM
Detected: 83.8 UG/L (ppb)
Found at 6 providers
A group of disinfection byproducts formed when chlorine reacts with organic matter. Long-term exposure above the legal limit has been linked to increased cancer risk in some studies.
Chloroform
Detected: 82.2 UG/L (ppb)
Found at 6 providers
One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.
Bromodichloromethane
Detected: 7.92 UG/L (ppb)
Found at 6 providers
Dibromochloromethane
Detected: 11.8 UG/L (ppb)
Found at 5 providers
Bromoform
Detected: 7.63 UG/L (ppb)
9/9/2025
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Chloride
Detected: 53.4 MG/L (ppm)
Found at 6 providers
Sulfate
Detected: 46.2 MG/L (ppm)
Found at 4 providers
Nitrate-Nitrite
Detected: 11.4 MG/L (ppm)
Found at 2 providers
Nitrate
Detected: 11.4 MG/L (ppm)
Found at 3 providers
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Fluoride
Detected: 0.446 MG/L (ppm)
6/30/2025
Often added deliberately for dental health; can also occur naturally.
Minerals
Everyday minerals that mainly affect taste and water hardness
Sodium
Detected: 34.3 MG/L (ppm)
Found at 6 providers
Calcium
Detected: 32.2 MG/L (ppm)
Found at 6 providers
Magnesium
Detected: 39 MG/L (ppm)
Found at 3 providers
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
Hardness, Total (ASCACO3)
Detected: 238 MG/L (ppm)
Found at 5 providers
pH
Detected: 8.5 PH
Found at 2 providers
A measure of how acidic or basic the water is (7 is neutral). Affects taste and plumbing, not a direct health measure.
Gross Alpha Particle Activity
Detected: 2.78 PCI/L
4/9/2025
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
PFPEA
Detected: 0.007 µg/L (ppb)
9/15/2025
PFBA
Detected: 0.0062 µg/L (ppb)
3/11/2025
PFHXS
Detected: 0.0041 µg/L (ppb)
9/15/2025
PFHPA
Detected: 0.0031 µg/L (ppb)
3/11/2025
PFOA
Detected: 0.004 µg/L (ppb)
3/11/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
PFHXA
Detected: 0.0059 µg/L (ppb)
9/15/2025
PFBS
Detected: 0.0046 µg/L (ppb)
9/15/2025
VOCs (Volatile Organic Compounds)
Industrial solvents and fuel-related chemicals that evaporate easily
Carbontetrachloride
Detected: 0.6 UG/L (ppb)
8/13/2025
Tetrachloroethylene
Detected: 1.9 UG/L (ppb)
10/14/2025
Calculated Parameters
Values worked out mathematically from other test results, not measured directly
Alkalinity, Bicarbonate
Detected: 150 MG/L (ppm)
Found at 5 providers
Alkalinity, Carbonate
Detected: 31.3 MG/L (ppm)
Found at 3 providers
Other
Additional substances tested that don't fit neatly into the categories above
Alkalinity, Total
Detected: 160 MG/L (ppm)
Found at 5 providers
TDS
Detected: 369 MG/L (ppm)
Found at 6 providers
Turbidity
Detected: 2.7 NTU
Found at 5 providers
A measure of water cloudiness from suspended particles.
Chlorate
Detected: 549 UG/L (ppb)
Found at 5 providers
Conductivity (at 25°C)
Detected: 626 UMHO/CM
Found at 6 providers
Dichloroaceticacid
Detected: 33.3 UG/L (ppb)
Found at 6 providers
Trichloroaceticacid
Detected: 40.6 UG/L (ppb)
Found at 6 providers
Monochloroaceticacid
Detected: 2.47 UG/L (ppb)
Found at 2 providers
Foamingagents (SURFACTANTS)
Detected: 0.12 MG/L (ppm)
Found at 2 providers
Carbon, Total
Detected: 2.28 MG/L (ppm)
Found at 3 providers
Perchlorate
Detected: 3.9 UG/L (ppb)
Found at 2 providers
Can occur naturally or from industrial/military sources; may interfere with thyroid function at elevated levels.
Color
Detected: 5 UNITS
Found at 3 providers
Monobromoaceticacid
Detected: 1.16 UG/L (ppb)
9/9/2025
Dibromoaceticacid
Detected: 3.35 UG/L (ppb)
9/9/2025
Aggressive Index
Detected: 13 AGGR
1/7/2025
Methyltert-Butylether
Detected: 0.58 UG/L (ppb)
10/7/2025
Odor
Detected: 16 TON
6/24/2025
Filtration considerations: General system types, not a specific product recommendation.