Is Gonzales, CA Tap Water Safe? Quality & Contaminants

What was found in Gonzales'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	6109.2 µg/L 61% of the EPA limit 10000 µg/L Main supplier: GONZALES, CITY OF · 8,327 people · 2019 Highest in the city: 82400 µg/L — RIVER RD WS #25 · 65 people · 2019	3/3	SYR4
Nitrate-Nitrite	39600 µg/L 396% of the EPA limit, at the 95th percentile of samples — 10000 µg/L Highest in the city: RIVER RD WS #25 · 65 people · 2018	2/3	SYR4
Fluoride	233 µg/L 5.8% of the EPA limit 4000 µg/L Main supplier: GONZALES, CITY OF · 8,327 people · 2018 Highest in the city: 235 µg/L — RIVER RD WS #25 · 65 people · 2015	3/3	SYR4
Barium	66.7 µg/L 3.3% of the EPA limit 2000 µg/L Highest in the city: WILLIAMS - RC FARMS WS · 35 people · 2017	1/3	SYR4
Lithium	33.4 µg/L No EPA limit set Main supplier: GONZALES, CITY OF · 8,327 people · 2023	1/3	UCMR-5
Combined Uranium	2.98 µg/L 9.9% of the EPA limit 30 µg/L Main supplier: GONZALES, CITY OF · 8,327 people · 2015 Highest in the city: 20.86 µg/L — RIVER RD WS #25 · 65 people · 2018	3/3	SYR4
Chromium	13 µg/L 13% of the EPA limit 100 µg/L Highest in the city: RIVER RD WS #25 · 65 people · 2015	1/3	SYR4
Selenium	7 µg/L 14% of the EPA limit 50 µg/L Highest in the city: RIVER RD WS #25 · 65 people · 2015	2/3	SYR4
TTHM	4.05 µg/L 5.1% of the EPA limit 80 µg/L Main supplier: GONZALES, CITY OF · 8,327 people · 2019	1/3	SYR4
Bromoform	3.33 µg/L No EPA limit set Main supplier: GONZALES, CITY OF · 8,327 people · 2019	1/3	SYR4
Arsenic	2 µg/L 20% of the EPA limit 10 µg/L Highest in the city: RIVER RD WS #25 · 65 people · 2015	2/3	SYR4
Dibromoacetic Acid	1.1 µg/L No EPA limit set Main supplier: GONZALES, CITY OF · 8,327 people · 2019	1/3	SYR4
Lead	0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: GONZALES, CITY OF · 8,327 people · 2024	3/3	LCR

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 Gonzales

Supplier	Population served
GONZALES, CITY OF	8,327
RIVER RD WS #25	65
WILLIAMS - RC FARMS WS	35

Frequently asked questions about Gonzales tap water

Is Gonzales tap water safe to drink?

EPA testing detected 13 contaminants in the water serving Gonzales. 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 Gonzales?

3 public water suppliers report drinking-water monitoring for Gonzales, California to the EPA. Each is listed above with its population served.

What contaminants are in Gonzales's water?

The contaminants EPA monitoring detected in Gonzales include Nitrate, Nitrate-Nitrite, Fluoride, Barium, Lithium. 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.