Serving roughly 120,377 people in Solano County, California.
Data current as of July 2026
🔍Straight from EPA
🧪Real Lab Results
📅Updated Quarterly
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Results for CITY OF FAIRFIELD
1 water provider directly on file, serving roughly 120,377 people in Solano County, California.
Quick answer: CITY OF FAIRFIELD currently has an open health-based violation on file: Lead And Copper Rule Revisions, a compliance issue since 10/17/2024. This is active, not historical — see the violation detail below for what EPA's enforcement record shows.
Lead Summary
Totalhaloaceticacids (HAA5)
TTHM
Chloroform
Bromoform
Bromodichloromethane
Dibromochloromethane
Trichloroaceticacid
Dichloroaceticacid
Dibromoaceticacid
Monochloroaceticacid
Aggressive Index
Temperature (CENTIGRADE)
Langelier Index (pH(s))
Langelier Index (Source Temp.)
Magnesium
Potassium
Sodium
Calcium
Nitrogen-Ammoniaas (N)
Alkalinity, Total
Alkalinity, Bicarbonate
Alkalinity, Carbonate
Hardness, Total (ASCACO3)
Carbon, Total
TDS
Chloride
Sulfate
Fluoride
Nitrate
Utility CITY OF FAIRFIELDPopulation served 120,377Owner Local government
Naturally occurring or corrosion-related elements, e.g. lead, arsenic, copper
Lead Summary
Detected: 0 mg/L (ppm)
12/31/2023
Disinfection Byproducts
Formed when chlorine used to disinfect water reacts with organic matter
Totalhaloaceticacids (HAA5)
Detected: 13 UG/L (ppb)
7/9/2025
TTHM
Detected: 25 UG/L (ppb)
7/9/2025
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: 18 UG/L (ppb)
7/9/2025
One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.
Bromoform
Detected: 0.52 UG/L (ppb)
1/15/2025
Bromodichloromethane
Detected: 5.5 UG/L (ppb)
7/9/2025
Dibromochloromethane
Detected: 1.8 UG/L (ppb)
7/9/2025
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Chloride
Detected: 9.7 MG/L (ppm)
10/8/2025
Sulfate
Detected: 38 MG/L (ppm)
10/8/2025
Fluoride
Detected: 0.735 MG/L (ppm)
10/8/2025
Often added deliberately for dental health; can also occur naturally.
Nitrate
Detected: 0.1 MG/L (ppm)
10/8/2025
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Minerals
Everyday minerals that mainly affect taste and water hardness
Magnesium
Detected: 20 MG/L (ppm)
10/8/2025
Potassium
Detected: 1.5 MG/L (ppm)
10/8/2025
Sodium
Detected: 23 MG/L (ppm)
10/8/2025
Calcium
Detected: 16 MG/L (ppm)
10/8/2025
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
Langelier Index (pH(s))
Detected: 0.84 LANG
10/8/2025
Hardness, Total (ASCACO3)
Detected: 135 MG/L (ppm)
10/8/2025
Calculated Parameters
Values worked out mathematically from other test results, not measured directly
Alkalinity, Bicarbonate
Detected: 120 MG/L (ppm)
10/8/2025
Alkalinity, Carbonate
Detected: 6.2 MG/L (ppm)
4/1/2025
Other
Additional substances tested that don't fit neatly into the categories above
Trichloroaceticacid
Detected: 5.6 UG/L (ppb)
7/9/2025
Dichloroaceticacid
Detected: 4.9 UG/L (ppb)
7/9/2025
Dibromoaceticacid
Detected: 1 UG/L (ppb)
4/2/2025
Monochloroaceticacid
Detected: 2.6 UG/L (ppb)
7/9/2025
Aggressive Index
Detected: 12 AGGR
10/8/2025
Temperature (CENTIGRADE)
Detected: 19 C
10/8/2025
Langelier Index (Source Temp.)
Detected: 0.24 LANG
10/8/2025
Nitrogen-Ammoniaas (N)
Detected: 0.062 MG/L (ppm)
1/7/2025
Alkalinity, Total
Detected: 120 MG/L (ppm)
10/8/2025
Carbon, Total
Detected: 1.9 MG/L (ppm)
10/8/2025
TDS
Detected: 200 MG/L (ppm)
10/8/2025
Filtration considerations: See the table below for how whole-house carbon, under-sink reverse osmosis, and under-sink carbon systems compare against what's actually on file here. These are general system types, not a specific product recommendation.