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EPA SDWIS · Santa Clara County, California

CITY OF GILROY Water Quality Report

Serving roughly 59,203 people in Santa Clara County, California.

Data current as of July 2026
🔍Straight from EPA
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Results for CITY OF GILROY

1 water provider directly on file, serving roughly 59,203 people in Santa Clara County, California.

Quick answer: CITY OF GILROY has no violations on file. One reading is worth knowing about: Perfluorobutanesulfonicacid (PFBS) was measured at 5.3NG/L, among the highest of the 320 providers on file in this area. It's the most notable figure in this system's record among its 320 local peers.
Utility CITY OF GILROY Population served 59,203 Owner Local government
No violations on file
Also serves GILROY

Contaminants found

Metals
Naturally occurring or corrosion-related elements, e.g. lead, arsenic, copper
Lead Summary
Detected: 0.002 mg/L (ppm)
12/31/2024
Chromium, Hex
Detected: 0.54 UG/L (ppb)
1/21/2025
Disinfection Byproducts
Formed when chlorine used to disinfect water reacts with organic matter
Totalhaloaceticacids (HAA5)
Detected: 1.9 UG/L (ppb)
7/21/2025
TTHM
Detected: 7.79 UG/L (ppb)
7/21/2025
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.
Bromoform
Detected: 4.68 UG/L (ppb)
7/21/2025
Dibromochloromethane
Detected: 3.11 UG/L (ppb)
7/21/2025
Bromodichloromethane
Detected: 1 UG/L (ppb)
4/23/2025
Inorganics
Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride
Nitrate
Detected: 4.6 MG/L (ppm)
7/21/2025
Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.
PFAS & Emerging Contaminants
Human-made "forever chemicals" and other substances not yet fully regulated
PFPEA
Detected: 0.0045 µg/L (ppb)
6/25/2025
PFHXA
Detected: 0.0036 µg/L (ppb)
6/25/2025
PFBS
Detected: 0.004 µg/L (ppb)
6/25/2025
PFHPA
Detected: 0.0036 µg/L (ppb)
12/17/2024
PFHXS
Detected: 0.0035 µg/L (ppb)
12/17/2024
PFOS
Detected: 0.0058 µg/L (ppb)
12/17/2024
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
PFOA
Detected: 0.0055 µg/L (ppb)
6/25/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Lithium
Detected: 11 µg/L (ppb)
6/25/2025
Occurs naturally in some groundwater. Not currently federally regulated in drinking water.
VOCs (Volatile Organic Compounds)
Industrial solvents and fuel-related chemicals that evaporate easily
Tetrachloroethylene
Detected: 0.85 UG/L (ppb)
9/29/2025
Other
Additional substances tested that don't fit neatly into the categories above
Dibromoaceticacid
Detected: 1.9 UG/L (ppb)
7/21/2025
Perfluorobutanesulfonicacid (PFBS)
Detected: 5.3 NG/L (ppt)
10/22/2025
Perfluoroctanoicacid (PFOA)
Detected: 5.2 NG/L (ppt)
10/22/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluorohexanoicacid (PFHXA)
Detected: 3.9 NG/L (ppt)
10/22/2025
Perfluoropentanoicacid (PFPEA)
Detected: 4 NG/L (ppt)
10/22/2025
Perfluoroheptanoicacid (PFHPA)
Detected: 3.2 NG/L (ppt)
3/24/2025
Perfluorohexanesulfonicacid (PFHxS)
Detected: 2.3 NG/L (ppt)
3/24/2025
Perfluoroctanesulfonicacid (PFOS)
Detected: 6.8 NG/L (ppt)
3/24/2025
One of two PFAS with an enforceable federal limit (4 ppt) since 2024.
Perfluorobutanoicacid (PFBA)
Detected: 4.5 NG/L (ppt)
3/24/2025
Radium-228
Detected: 0.828 PCI/L
9/3/2025
Combined Radium (-226 & -228)
Detected: 0.828 PCI/L
9/3/2025
A naturally occurring radioactive element found in some groundwater.
Perchlorate
Detected: 2.6 UG/L (ppb)
7/21/2025
Can occur naturally or from industrial/military sources; may interfere with thyroid function at elevated levels.
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.
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
LeadPartialYesPartial
ArsenicPartialYesPartial
Chromium-6 (Hexavalent)PartialYesPartial
CopperPartialYesPartial
Combined UraniumPartialYesPartial
PFOAPartialYes*Partial
PFOSPartialYes*Partial
NitratePartialYesPartial
Combined RadiumPartialYesPartial
PFPEAPartialYes*Partial
PFHXAPartialYes*Partial
PFBSPartialYes*Partial
PFHPAPartialYes*Partial
PFHXSPartialYes*Partial
LithiumPartialYes*Partial
DibromoaceticacidPartialYesPartial
Perfluorobutanesulfonicacid (PFBS)PartialYesPartial
Perfluoroctanoicacid (PFOA)PartialYesPartial
Perfluorohexanoicacid (PFHXA)PartialYesPartial
Perfluoropentanoicacid (PFPEA)PartialYesPartial
Perfluoroheptanoicacid (PFHPA)PartialYesPartial
Perfluorohexanesulfonicacid (PFHxS)PartialYesPartial
Perfluoroctanesulfonicacid (PFOS)PartialYesPartial
Perfluorobutanoicacid (PFBA)PartialYesPartial
Combined Radium (-226 & -228)PartialYesPartial
Chromium, HexPartialYesPartial
PerchloratePartialYesPartial
Coliform Bacteria (indicator)NoYesNo

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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?