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Water Quality Lookup / California / San Benito County
EPA SDWIS ยท San Benito County, California ยท 149 providers profiled

San Benito County, CA Water Quality Report

San Benito County is served by 149 major public water systems on file with the EPA.

Data current as of July 2026
๐Ÿ”Straight from EPA
๐ŸงชReal Lab Results
๐Ÿ“…Updated Quarterly
๐Ÿ Local Expertise
Results for San Benito County, CA

149 water providers on file for this county, sorted by population served.

Quick answer: San Benito County has 149 water providers profiled, sorted by population served.

Violations on file

Coliform (TCR)
Older/archived health-based violation
Found at 4 of 149 providers
Surface Water Treatment Rule
Older/archived health-based violation
Found at 3 of 149 providers
Nitrate
Older/archived health-based violation
Found at 3 of 149 providers
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
TTHM
Older/archived health-based violation
Found at 1 of 149 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.
Arsenic
Older/archived health-based violation
Found at 4 of 149 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.
Lead And Copper Rule Revisions
Currently open health violation
Found at 8 of 149 providers
Revised Total Coliform Rule
Currently open health violation
Found at 2 of 149 providers
Carbon, Total
Older/archived health-based violation
Found at 1 of 149 providers
Fluoride
Older/archived health-based violation
Found at 1 of 149 providers
Often added deliberately for dental health; can also occur naturally.
Nitrate-Nitrite
Older/archived health-based violation
Found at 1 of 149 providers
Chlorine
Older/archived health-based violation
Found at 1 of 149 providers

Contaminants found

Metals
Naturally occurring or corrosion-related elements, e.g. lead, arsenic, copper
Lead Summary
Detected: 0.0453 mg/L (ppm)
Found at 61 providers
Copper, Free
Detected: 260 UG/L (ppb)
Found at 20 providers
Iron
Detected: 5900 UG/L (ppb)
Found at 18 providers
Mostly an aesthetic issue (metallic taste, staining) rather than a health concern at typical levels.
Arsenic
Detected: 118 UG/L (ppb)
Found at 17 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.
Aluminum
Detected: 1350 UG/L (ppb)
Found at 6 providers
Chromium, Hex
Detected: 41 UG/L (ppb)
Found at 20 providers
Chromium
Detected: 35 UG/L (ppb)
Found at 5 providers
Occurs in two forms โ€” trivalent (an essential nutrient in trace amounts) and hexavalent (linked to increased cancer risk).
Barium
Detected: 256 UG/L (ppb)
Found at 11 providers
Selenium
Detected: 29 UG/L (ppb)
Found at 13 providers
Combined Uranium
Detected: 20.5 PCI/L
Found at 9 providers
A naturally occurring radioactive metal. Long-term exposure above the legal limit is associated with kidney effects and increased cancer risk.
Manganese
Detected: 886 UG/L (ppb)
Found at 23 providers
Mainly a taste/staining concern at typical levels; long-term neurological research at high chronic exposure is ongoing.
Copper Summary
Detected: 4.55 mg/L (ppm)
Found at 10 providers
Lead
Detected: 66.7 UG/L (ppb)
Found at 6 providers
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.
Nickel
Detected: 14.7 UG/L (ppb)
Found at 3 providers
Zinc
Detected: 81 UG/L (ppb)
Found at 3 providers
Disinfection Byproducts
Formed when chlorine used to disinfect water reacts with organic matter
Totalhaloaceticacids (HAA5)
Detected: 350 UG/L (ppb)
Found at 10 providers
TTHM
Detected: 97 UG/L (ppb)
Found at 22 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.
Dibromochloromethane
Detected: 39 UG/L (ppb)
Found at 23 providers
Chloroform
Detected: 390 UG/L (ppb)
Found at 10 providers
One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.
Bromodichloromethane
Detected: 87 UG/L (ppb)
Found at 15 providers
Bromoform
Detected: 45 UG/L (ppb)
Found at 22 providers
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Nitrate
Detected: 36 MG/L (ppm)
Found at 44 providers
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
Nitrate-Nitrite
Detected: 6.6 MG/L (ppm)
Found at 11 providers
Chloride
Detected: 620 MG/L (ppm)
Found at 14 providers
Sulfate
Detected: 948 MG/L (ppm)
Found at 11 providers
Boron, Total
Detected: 830 UG/L (ppb)
4/16/2025
Fluoride
Detected: 0.41 MG/L (ppm)
Found at 11 providers
Often added deliberately for dental health; can also occur naturally.
Nitrite
Detected: 0.07 MG/L (ppm)
Found at 2 providers
Minerals
Everyday minerals that mainly affect taste and water hardness
Magnesium
Detected: 272 MG/L (ppm)
Found at 14 providers
Sodium
Detected: 420 MG/L (ppm)
Found at 14 providers
Calcium
Detected: 206 MG/L (ppm)
Found at 15 providers
Potassium
Detected: 16 MG/L (ppm)
Found at 10 providers
Properties
General water characteristics like pH, hardness, and cloudiness (turbidity)
Hardness, Total (ASCACO3)
Detected: 1630 MG/L (ppm)
Found at 13 providers
pH
Detected: 8.2 PH
Found at 15 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: 21.6 PCI/L
Found at 10 providers
Langelier Index (pH(s))
Detected: 1.54 LANG
Found at 10 providers
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
Lithium
Detected: 32 ยตg/L (ppb)
Found at 4 providers
Occurs naturally in some groundwater. Not currently federally regulated in drinking water.
PFOA
Detected: 0.0046 ยตg/L (ppb)
5/13/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
VOCs (Volatile Organic Compounds)
Industrial solvents and fuel-related chemicals that evaporate easily
Bromide
Detected: 2 MG/L (ppm)
Found at 5 providers
Calculated Parameters
Values worked out mathematically from other test results, not measured directly
Alkalinity, Bicarbonate
Detected: 710 MG/L (ppm)
Found at 14 providers
Other
Additional substances tested that don't fit neatly into the categories above
Nitrogen-Ammoniaas (N)
Detected: 0.34 MG/L (ppm)
5/21/2025
Dichloroaceticacid
Detected: 140 UG/L (ppb)
Found at 10 providers
Trichloroaceticacid
Detected: 8 UG/L (ppb)
Found at 6 providers
Monobromoaceticacid
Detected: 4.1 UG/L (ppb)
Found at 5 providers
Dibromoaceticacid
Detected: 12 UG/L (ppb)
Found at 20 providers
Monochloroaceticacid
Detected: 210 UG/L (ppb)
Found at 3 providers
Alkalinity, Total
Detected: 710 MG/L (ppm)
Found at 15 providers
TDS
Detected: 2850 MG/L (ppm)
Found at 14 providers
Conductivity (at 25ยฐC)
Detected: 4800 UMHO/CM
Found at 15 providers
Radium-228
Detected: 0.437 PCI/L
Found at 6 providers
Combined Radium (-226 & -228)
Detected: 1.12 PCI/L
Found at 4 providers
A naturally occurring radioactive element found in some groundwater.
Aggressive Index
Detected: 12.9 AGGR
Found at 11 providers
Turbidity
Detected: 4.4 NTU
Found at 10 providers
A measure of water cloudiness from suspended particles.
Carbon, Total
Detected: 1.72 MG/L (ppm)
Found at 2 providers
Langelier Index (Source Temp.)
Detected: 0.72 LANG
Found at 6 providers
Color
Detected: 25 UNITS
Found at 7 providers
Perfluorobutanesulfonicacid (PFBS)
Detected: 4.9 NG/L (ppt)
7/17/2025
Perfluorohexanesulfonicacid (PFHxS)
Detected: 2.8 NG/L (ppt)
7/17/2025
Perfluorobutanoicacid (PFBA)
Detected: 2.9 NG/L (ppt)
7/17/2025
Perfluoropentanoicacid (PFPEA)
Detected: 2.7 NG/L (ppt)
7/17/2025
Odor
Detected: 2 TON
Found at 3 providers
N-Nitrosodimethylamine
Detected: 0.012 UG/L (ppb)
10/22/2025
Perchlorate
Detected: 1.7 UG/L (ppb)
10/29/2025
Can occur naturally or from industrial/military sources; may interfere with thyroid function at elevated levels.
Foamingagents (SURFACTANTS)
Detected: 0.14 MG/L (ppm)
Found at 3 providers
Asbestos
Detected: 1.2 MFL
3/25/2025
Filtration considerations: General system types, not a specific product recommendation.
Contaminant Whole-House Carbon Under-Sink RO Under-Sink Carbon
Total Trihalomethanes (TTHM)YesYesYes
Haloacetic Acids (HAA5)YesYesYes
ChloroformYesYesYes
Chlorine / TasteYesYesYes
Sediment / TurbidityYesYesYes
TrichloroethyleneYesYesYes
TetrachloroethyleneYesYesYes
cis-1,2-DichloroethyleneYesYesYes
1,1-DichloroethyleneYesYesYes
BromoformYesYesYes
BromodichloromethaneYesYesYes
DibromochloromethaneYesYesYes
1,1,2-TrichloroethaneYesYesYes
Vinyl ChlorideYesYesYes
Carbon TetrachlorideYesYesYes
BenzeneYesYesYes
TolueneYesYesYes
XyleneYesYesYes
Totalhaloaceticacids (HAA5)YesYesYes
BromideYesYesYes
LeadPartialYesPartial
ArsenicPartialYesPartial
Chromium-6 (Hexavalent)PartialYesPartial
CopperPartialYesPartial
Combined UraniumPartialYesPartial
PFOAPartialYes*Partial
PFOSPartialYes*Partial
NitratePartialYesPartial
Combined RadiumPartialYesPartial
Copper, FreePartialYesPartial
IronPartialYesPartial
Nitrogen-Ammoniaas (N)PartialYesPartial
AluminumPartialYesPartial
DichloroaceticacidPartialYesPartial
TrichloroaceticacidPartialYesPartial
MonobromoaceticacidPartialYesPartial
DibromoaceticacidPartialYesPartial
MonochloroaceticacidPartialYesPartial
Chromium, HexPartialYesPartial
Nitrate-NitritePartialYesPartial
ChromiumPartialYesPartial
BariumPartialYesPartial
SeleniumPartialYesPartial
LithiumPartialYes*Partial
Alkalinity, TotalPartialYesPartial
TDSPartialYesPartial
ChloridePartialYesPartial
SulfatePartialYesPartial
Boron, TotalPartialYesPartial
Conductivity (at 25ยฐC)PartialYesPartial
Combined UraniumPartialYesPartial
ManganesePartialYesPartial
Combined Radium (-226 & -228)PartialYesPartial
Aggressive IndexPartialYesPartial
FluoridePartialYesPartial
Carbon, TotalPartialYesPartial
Langelier Index (Source Temp.)PartialYesPartial
NickelPartialYesPartial
ColorPartialYesPartial
Perfluorobutanesulfonicacid (PFBS)PartialYesPartial
Perfluorohexanesulfonicacid (PFHxS)PartialYesPartial
Perfluorobutanoicacid (PFBA)PartialYesPartial
Perfluoropentanoicacid (PFPEA)PartialYesPartial
NitritePartialYesPartial
OdorPartialYesPartial
ZincPartialYesPartial
N-NitrosodimethylaminePartialYesPartial
PerchloratePartialYesPartial
Foamingagents (SURFACTANTS)PartialYesPartial
AsbestosPartialYesPartial
Coliform Bacteria (indicator)NoYesNo
MagnesiumNoPartialNo
SodiumNoPartialNo
CalciumNoPartialNo
Alkalinity, BicarbonateNoNoNo
Hardness, Total (ASCACO3)NoNoNo
PotassiumNoPartialNo
pHNoNoNo
Gross Alpha Particle ActivityNoNoNo
Langelier Index (pH(s))NoNoNo

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What is TTHM? Understanding EPA Violation Status Is Chromium-6 Dangerous? Whole-House vs. Under-Sink Filtration Lead and Copper in Drinking Water What is PFAS? Arsenic and Uranium Explained Nitrate and Fluoride Explained Water Hardness, pH, and Turbidity What is Coliform Bacteria?