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Tap water quality report

Norwalk, CA

EPA monitoring detected 23 contaminants across the 1 water supplier serving Norwalk. A detection doesn't automatically mean the water is unsafe — see the level at the main supplier for each below, with its EPA source and period.

1
water supplier
20,283
people served
23
contaminants found
California rankings Lead in California PFAS in California

What was found in Norwalk'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.

ContaminantLevel vs EPA limitSuppliersSource
Nitrate
3616 µg/L 36%
of the EPA limit 10000 µg/L
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2019
1/1 SYR4
Fluoride
379.5 µg/L 9.5%
of the EPA limit 4000 µg/L
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2019
1/1 SYR4
Barium
120 µg/L 6%
of the EPA limit 2000 µg/L
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2019
1/1 SYR4
Lithium
59 µg/L
No EPA limit set
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2024
1/1 UCMR-5
TTHM
47.74 µg/L 60%
of the EPA limit 80 µg/L
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2019
1/1 SYR4
Dibromochloromethane
16.8 µg/L
No EPA limit set
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2019
1/1 SYR4
Total Haloacetic Acids (HAA5)
15.195 µg/L 25%
of the EPA limit 60 µg/L
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2019
1/1 SYR4
Bromodichloromethane
14.14 µg/L
No EPA limit set
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2019
1/1 SYR4
Chloroform
13.2 µg/L
No EPA limit set
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2019
1/1 SYR4
Bromoform
10.1 µg/L
No EPA limit set
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2019
1/1 SYR4
Combined Uranium
8.5973 µg/L 29%
of the EPA limit 30 µg/L
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2019
1/1 SYR4
Dichloroacetic Acid
8.39 µg/L
No EPA limit set
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2019
1/1 SYR4
Trichloroacetic Acid
5.93 µg/L
No EPA limit set
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2019
1/1 SYR4
Dibromoacetic Acid
5.655 µg/L
No EPA limit set
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2019
1/1 SYR4
Arsenic
3.79 µg/L 38%
of the EPA limit 10 µg/L
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2019
1/1 SYR4
Tetrachloroethylene
3.4 µg/L 68%
of the EPA limit 5 µg/L
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2019
1/1 SYR4
Trichloroethylene
2.73 µg/L 55%
of the EPA limit 5 µg/L
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2019
1/1 SYR4
PFOS
0.0260 µg/L
No EPA limit set
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2024
1/1 UCMR-5
PFHXS
0.0076 µg/L
No EPA limit set
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2024
1/1 UCMR-5
Pfba
0.0056 µg/L
No EPA limit set
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2024
1/1 UCMR-5
PFOA
0.0052 µg/L
No EPA limit set
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2024
1/1 UCMR-5
Pfpea
0.0034 µg/L
No EPA limit set
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2024
1/1 UCMR-5
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
Main supplier: NORWALK - CITY, WATER DEPT. · 20,283 people · 2022
1/1 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 Norwalk

SupplierPopulation served
NORWALK - CITY, WATER DEPT. 20,283

Frequently asked questions about Norwalk tap water

Is Norwalk tap water safe to drink?

EPA testing detected 23 contaminants in the water serving Norwalk. 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 Norwalk?

1 public water supplier report drinking-water monitoring for Norwalk, California to the EPA. Each is listed above with its population served.

What contaminants are in Norwalk's water?

The contaminants EPA monitoring detected in Norwalk include Nitrate, Fluoride, Barium, Lithium, 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.