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Tap water quality report

Hawthorne, CA

EPA monitoring detected 19 contaminants across the 2 water suppliers serving Hawthorne. 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.

2
water suppliers
322,458
people served
19
contaminants found
California rankings Lead in California PFAS in California

What was found in Hawthorne'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
Fluoride
697.5 µg/L 17%
of the EPA limit 4000 µg/L
Main supplier: GSWC - SOUTHWEST · 277,740 people · 2019
Highest in the city: 841.8 µg/L — HAWTHORNE-CITY WATER DEPT. · 44,718 people · 2019
2/2 SYR4
Barium
120 µg/L 6%
of the EPA limit 2000 µg/L
Main supplier: GSWC - SOUTHWEST · 277,740 people · 2017
1/2 SYR4
TTHM
59.25 µg/L 74%
of the EPA limit 80 µg/L
Main supplier: GSWC - SOUTHWEST · 277,740 people · 2019
Highest in the city: 98.195 µg/L — HAWTHORNE-CITY WATER DEPT. · 44,718 people · 2019
2/2 SYR4
Lithium
51.3 µg/L
No EPA limit set
Main supplier: GSWC - SOUTHWEST · 277,740 people · 2025
2/2 UCMR-5
Dibromochloromethane
17 µg/L
No EPA limit set
Main supplier: GSWC - SOUTHWEST · 277,740 people · 2019
Highest in the city: 36.2905 µg/L — HAWTHORNE-CITY WATER DEPT. · 44,718 people · 2019
2/2 SYR4
Total Haloacetic Acids (HAA5)
27.4 µg/L 46%
of the EPA limit 60 µg/L
Main supplier: GSWC - SOUTHWEST · 277,740 people · 2019
2/2 SYR4
Bromoform
9.76 µg/L
No EPA limit set
Main supplier: GSWC - SOUTHWEST · 277,740 people · 2019
Highest in the city: 26.0195 µg/L — HAWTHORNE-CITY WATER DEPT. · 44,718 people · 2019
2/2 SYR4
Bromodichloromethane
18 µg/L
No EPA limit set
Main supplier: GSWC - SOUTHWEST · 277,740 people · 2019
Highest in the city: 21.2715 µg/L — HAWTHORNE-CITY WATER DEPT. · 44,718 people · 2019
2/2 SYR4
Copper
20.56 µg/L 1.6%
of the EPA limit 1300 µg/L
Highest in the city: HAWTHORNE-CITY WATER DEPT. · 44,718 people · 2019
1/2 SYR4
Chloroform
20 µg/L
No EPA limit set
Main supplier: GSWC - SOUTHWEST · 277,740 people · 2019
2/2 SYR4
Dichloroacetic Acid
11 µg/L
No EPA limit set
Main supplier: GSWC - SOUTHWEST · 277,740 people · 2019
2/2 SYR4
Dibromoacetic Acid
5.71 µg/L
No EPA limit set
Main supplier: GSWC - SOUTHWEST · 277,740 people · 2019
Highest in the city: 10 µg/L — HAWTHORNE-CITY WATER DEPT. · 44,718 people · 2019
2/2 SYR4
Trichloroacetic Acid
8.87 µg/L
No EPA limit set
Main supplier: GSWC - SOUTHWEST · 277,740 people · 2019
2/2 SYR4
Monochloroacetic Acid
5.64 µg/L
No EPA limit set
Main supplier: GSWC - SOUTHWEST · 277,740 people · 2019
2/2 SYR4
Selenium
5.3 µg/L 11%
of the EPA limit 50 µg/L
Highest in the city: HAWTHORNE-CITY WATER DEPT. · 44,718 people · 2019
1/2 SYR4
Combined Uranium
5.215 µg/L 17%
of the EPA limit 30 µg/L
Main supplier: GSWC - SOUTHWEST · 277,740 people · 2019
1/2 SYR4
Arsenic
2.94 µg/L 29%
of the EPA limit 10 µg/L
Main supplier: GSWC - SOUTHWEST · 277,740 people · 2017
1/2 SYR4
Monobromoacetic Acid
2.1 µg/L
No EPA limit set
Main supplier: GSWC - SOUTHWEST · 277,740 people · 2019
2/2 SYR4
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
Main supplier: GSWC - SOUTHWEST · 277,740 people · 2022
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 Hawthorne

SupplierPopulation served
GSWC - SOUTHWEST 277,740
HAWTHORNE-CITY WATER DEPT. 44,718

Frequently asked questions about Hawthorne tap water

Is Hawthorne tap water safe to drink?

EPA testing detected 19 contaminants in the water serving Hawthorne. 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 Hawthorne?

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

What contaminants are in Hawthorne's water?

The contaminants EPA monitoring detected in Hawthorne include Fluoride, Barium, TTHM, Lithium, Dibromochloromethane. 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.