Is Lathrop, CA Tap Water Safe? Quality & Contaminants

What was found in Lathrop'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	8051.25 µg/L 81% of the EPA limit 10000 µg/L Main supplier: CITY OF LATHROP · 35,080 people · 2019	1/2	SYR4
Nitrate-Nitrite	5560 µg/L 56% of the EPA limit 10000 µg/L Main supplier: CITY OF LATHROP · 35,080 people · 2017	1/2	SYR4
Barium	335 µg/L 17% of the EPA limit 2000 µg/L Main supplier: CITY OF LATHROP · 35,080 people · 2017 Highest in the city: 452.2 µg/L — HAVEN ACRES RIVER CLUB INC · 100 people · 2017	2/2	SYR4
Fluoride	128 µg/L 3.2% of the EPA limit 4000 µg/L Main supplier: CITY OF LATHROP · 35,080 people · 2017	1/2	SYR4
TTHM	51.25 µg/L 64% of the EPA limit 80 µg/L Main supplier: CITY OF LATHROP · 35,080 people · 2019	1/2	SYR4
Chloroform	50 µg/L No EPA limit set Main supplier: CITY OF LATHROP · 35,080 people · 2019	1/2	SYR4
Combined Uranium	48.2834 µg/L 161% of the EPA limit, at the 95th percentile of samples — 30 µg/L Main supplier: CITY OF LATHROP · 35,080 people · 2019	2/2	SYR4
Total Haloacetic Acids (HAA5)	42 µg/L 70% of the EPA limit 60 µg/L Main supplier: CITY OF LATHROP · 35,080 people · 2019	1/2	SYR4
Trichloroacetic Acid	25 µg/L No EPA limit set Main supplier: CITY OF LATHROP · 35,080 people · 2019	1/2	SYR4
Dichloroacetic Acid	22.7 µg/L No EPA limit set Main supplier: CITY OF LATHROP · 35,080 people · 2019	1/2	SYR4
Arsenic	20 µg/L 200% of the EPA limit, at the 95th percentile of samples — 10 µg/L Main supplier: CITY OF LATHROP · 35,080 people · 2019	2/2	SYR4
Bromoform	13 µg/L No EPA limit set Main supplier: CITY OF LATHROP · 35,080 people · 2019	1/2	SYR4
Dibromochloromethane	6.79 µg/L No EPA limit set Main supplier: CITY OF LATHROP · 35,080 people · 2019	1/2	SYR4
Gross Beta Particle Activity	5.2 pCi/L No EPA limit set Main supplier: CITY OF LATHROP · 35,080 people · 2016	1/2	SYR4
Selenium	5 µg/L 10% of the EPA limit 50 µg/L Highest in the city: HAVEN ACRES RIVER CLUB INC · 100 people · 2017	1/2	SYR4
Bromodichloromethane	3.467 µg/L No EPA limit set Main supplier: CITY OF LATHROP · 35,080 people · 2019	1/2	SYR4
Dibromoacetic Acid	3.425 µg/L No EPA limit set Main supplier: CITY OF LATHROP · 35,080 people · 2019	1/2	SYR4
Chromium	3 µg/L 3% of the EPA limit 100 µg/L Main supplier: CITY OF LATHROP · 35,080 people · 2017	1/2	SYR4
Monobromoacetic Acid	2.58 µg/L No EPA limit set Main supplier: CITY OF LATHROP · 35,080 people · 2019	1/2	SYR4
Monochloroacetic Acid	2.075 µg/L No EPA limit set Main supplier: CITY OF LATHROP · 35,080 people · 2019	1/2	SYR4
Lead	0.2000 µg/L 1.3% of the EPA limit 15 µg/L Main supplier: CITY OF LATHROP · 35,080 people · 2017	1/2	SYR4
PFOS	0.0170 µg/L No EPA limit set Main supplier: CITY OF LATHROP · 35,080 people · 2024	1/2	UCMR-5
PFBS	0.0050 µg/L No EPA limit set Main supplier: CITY OF LATHROP · 35,080 people · 2024	1/2	UCMR-5
PFHXS	0.0035 µg/L No EPA limit set Main supplier: CITY OF LATHROP · 35,080 people · 2024	1/2	UCMR-5
Lead	0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: CITY OF LATHROP · 35,080 people · 2024	2/2	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 Lathrop

Supplier	Population served
CITY OF LATHROP	35,080
HAVEN ACRES RIVER CLUB INC	100

Frequently asked questions about Lathrop tap water

Is Lathrop tap water safe to drink?

EPA testing detected 25 contaminants in the water serving Lathrop. 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 Lathrop?

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

What contaminants are in Lathrop's water?

The contaminants EPA monitoring detected in Lathrop include Nitrate, Nitrate-Nitrite, Barium, Fluoride, TTHM. 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.