What was found in Gilroy's water
The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate-Nitrite | 8460 µg/L 85% of the EPA limit 10000 µg/L Main supplier: CITY OF GILROY · 59,203 people · 2018
Highest in the city: 380020 µg/L — QUAIL CREEK ESTATES MUTUAL WATER COMPANY · 55 people · 2018 | 10/12 | SYR4 |
| Nitrate | 8588 µg/L 86% of the EPA limit 10000 µg/L Main supplier: CITY OF GILROY · 59,203 people · 2019
Highest in the city: 23000 µg/L — VALLEY VIEW RANCHES · 45 people · 2019 | 9/12 | SYR4 |
| Fluoride | 170 µg/L 4.3% of the EPA limit 4000 µg/L Main supplier: CITY OF GILROY · 59,203 people · 2018
Highest in the city: 455 µg/L — QUAIL CREEK ESTATES MUTUAL WATER COMPANY · 55 people · 2018 | 10/12 | SYR4 |
| Nitrite | 380.02 µg/L 38% of the EPA limit 1000 µg/L Highest in the city: QUAIL CREEK ESTATES MUTUAL WATER COMPANY · 55 people · 2018 | 1/12 | SYR4 |
| Barium | 140 µg/L 7% of the EPA limit 2000 µg/L Main supplier: CITY OF GILROY · 59,203 people · 2018
Highest in the city: 242 µg/L — GOLDEN HEIGHTS MUTUAL WATER COMPANY · 66 people · 2017 | 8/12 | SYR4 |
| Copper | 91.9 µg/L 7.1% of the EPA limit 1300 µg/L Highest in the city: ANGELO LANE WATER COMPANY · 41 people · 2019 | 3/12 | SYR4 |
| Cyanide | 54 µg/L 27% of the EPA limit 200 µg/L Highest in the city: LOS RANCHOS DE UVAS WATER COMPANY · 58 people · 2019 | 2/12 | SYR4 |
| TTHM | 11 µg/L 14% of the EPA limit 80 µg/L Main supplier: CITY OF GILROY · 59,203 people · 2019
Highest in the city: 27.4 µg/L — QUAIL CREEK ESTATES MUTUAL WATER COMPANY · 55 people · 2019 | 4/12 | SYR4 |
| Lead | 12.95 µg/L 86% of the EPA limit 15 µg/L Highest in the city: LOS RANCHOS DE UVAS WATER COMPANY · 58 people · 2018 | 4/12 | SYR4 |
| Bromoform | 10.235 µg/L No EPA limit set Main supplier: CITY OF GILROY · 59,203 people · 2019
Highest in the city: 11.44 µg/L — QUAIL CREEK ESTATES MUTUAL WATER COMPANY · 55 people · 2019 | 3/12 | SYR4 |
| Dibromochloromethane | 1.7725 µg/L No EPA limit set Main supplier: CITY OF GILROY · 59,203 people · 2019
Highest in the city: 11 µg/L — QUAIL CREEK ESTATES MUTUAL WATER COMPANY · 55 people · 2019 | 4/12 | SYR4 |
| Lithium | 11 µg/L No EPA limit set Main supplier: CITY OF GILROY · 59,203 people · 2025 | 1/12 | UCMR-5 |
| Total Haloacetic Acids (HAA5) | 4.49 µg/L 7.5% of the EPA limit 60 µg/L Main supplier: CITY OF GILROY · 59,203 people · 2019
Highest in the city: 8.975 µg/L — QUAIL CREEK ESTATES MUTUAL WATER COMPANY · 55 people · 2019 | 4/12 | SYR4 |
| Chromium | 8.65 µg/L 8.7% of the EPA limit 100 µg/L Highest in the city: QUAIL CREEK ESTATES MUTUAL WATER COMPANY · 55 people · 2018 | 5/12 | SYR4 |
| Selenium | 7 µg/L 14% of the EPA limit 50 µg/L Highest in the city: LOS RANCHOS DE UVAS WATER COMPANY · 58 people · 2018 | 1/12 | SYR4 |
| Dibromoacetic Acid | 2.91 µg/L No EPA limit set Main supplier: CITY OF GILROY · 59,203 people · 2019
Highest in the city: 6.36 µg/L — QUAIL CREEK ESTATES MUTUAL WATER COMPANY · 55 people · 2019 | 4/12 | SYR4 |
| Bromodichloromethane | 5.08 µg/L No EPA limit set Highest in the city: QUAIL CREEK ESTATES MUTUAL WATER COMPANY · 55 people · 2019 | 2/12 | SYR4 |
| Dichloroacetic Acid | 3.69 µg/L No EPA limit set Main supplier: CITY OF GILROY · 59,203 people · 2019 | 2/12 | SYR4 |
| Tetrachloroethylene | 2.7 µg/L 54% of the EPA limit 5 µg/L Main supplier: CITY OF GILROY · 59,203 people · 2019 | 1/12 | SYR4 |
| Chloroform | 2.1 µg/L No EPA limit set Highest in the city: QUAIL CREEK ESTATES MUTUAL WATER COMPANY · 55 people · 2019 | 2/12 | SYR4 |
| Arsenic | 1.935 µg/L 19% of the EPA limit 10 µg/L Highest in the city: QUAIL CREEK ESTATES MUTUAL WATER COMPANY · 55 people · 2018 | 2/12 | SYR4 |
| Trichloroacetic Acid | 1.9 µg/L No EPA limit set Main supplier: CITY OF GILROY · 59,203 people · 2019 | 1/12 | SYR4 |
| PFBS | 0.0094 µg/L No EPA limit set Main supplier: CITY OF GILROY · 59,203 people · 2025 | 1/12 | UCMR-5 |
| PFOA | 0.0080 µg/L No EPA limit set Main supplier: CITY OF GILROY · 59,203 people · 2025 | 1/12 | UCMR-5 |
| Pfpea | 0.0078 µg/L No EPA limit set Main supplier: CITY OF GILROY · 59,203 people · 2025 | 1/12 | UCMR-5 |
| Pfhxa | 0.0070 µg/L No EPA limit set Main supplier: CITY OF GILROY · 59,203 people · 2025 | 1/12 | UCMR-5 |
| Lead | 0.0020 mg/L 13% of the EPA limit 0.0150 mg/L Main supplier: CITY OF GILROY · 59,203 people · 2024
Highest in the city: 0.0060 mg/L — LIVE OAK CREEK MUTUAL WATER COMPANY · 30 people · 2025 | 12/12 | LCR |
| PFOS | 0.0058 µg/L No EPA limit set Main supplier: CITY OF GILROY · 59,203 people · 2025 | 1/12 | UCMR-5 |
| Pfhpa | 0.0036 µg/L No EPA limit set Main supplier: CITY OF GILROY · 59,203 people · 2025 | 1/12 | UCMR-5 |
| PFHXS | 0.0035 µg/L No EPA limit set Main supplier: CITY OF GILROY · 59,203 people · 2025 | 1/12 | UCMR-5 |
Each bar shows the measured level as a share of the EPA limit: green is
well under, amber is close to it, red is over. For lead and copper the
limit applies to exactly the 90th-percentile figure shown, so red there
means a real exceedance. For everything else the limit applies to a
running annual average while the figure is the 95th percentile of the
system's samples — over 100% is worth reading, but is not by itself a
violation.
Formal violations are listed separately.
These are the utilities' own EPA-reported results, not a city-wide
average. A detection means the lab measured the
substance — it isn't the same as exceeding a legal limit. Hover a source
tag to see the EPA program and years behind each figure.
Water suppliers serving Gilroy
Frequently asked questions about Gilroy tap water
Is Gilroy tap water safe to drink?
EPA testing detected 30 contaminants in the water serving Gilroy. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.
How many water suppliers serve Gilroy?
12 public water suppliers report drinking-water monitoring for Gilroy, California to the EPA. Each is listed above with its population served.
What contaminants are in Gilroy's water?
The contaminants EPA monitoring detected in Gilroy include Nitrate-Nitrite, Nitrate, Fluoride, Nitrite, Barium. The full list, with the level at the main supplier and the data source, is in the table above.
Where does this data come from?
Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.