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Tap water quality report

Rialto, CA

EPA monitoring detected 42 contaminants across the 2 water suppliers serving Rialto. 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
158,951
people served
42
contaminants found
California rankings Lead in California PFAS in California

What was found in Rialto'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-Nitrite
451999.99999999994 µg/L 4520%
of the EPA limit, at the 95th percentile of samples — 10000 µg/L
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
2/2 SYR4
Nitrate
8588 µg/L 86%
of the EPA limit 10000 µg/L
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
2/2 SYR4
Fluoride
410 µg/L 10%
of the EPA limit 4000 µg/L
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
2/2 SYR4
Copper
83 µg/L 6.4%
of the EPA limit 1300 µg/L
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
Highest in the city: 140 µg/L — RIALTO, CITY OF · 54,453 people · 2019
2/2 SYR4
TTHM
65.17999999999999 µg/L 81%
of the EPA limit 80 µg/L
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
2/2 SYR4
Toluene
1.7 µg/L 0.2%
of the EPA limit 1000 µg/L
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
Highest in the city: 49.599999999999994 µg/L — RIALTO, CITY OF · 54,453 people · 2019
2/2 SYR4
Barium
46.29999999999998 µg/L 2.3%
of the EPA limit 2000 µg/L
Highest in the city: RIALTO, CITY OF · 54,453 people · 2019
1/2 SYR4
Dibromochloromethane
23.574999999999996 µg/L
No EPA limit set
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
2/2 SYR4
Bromodichloromethane
19.389999999999997 µg/L
No EPA limit set
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
2/2 SYR4
Chloroform
18.025 µg/L
No EPA limit set
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
2/2 SYR4
Total Haloacetic Acids (HAA5)
16.039999999999978 µg/L 27%
of the EPA limit 60 µg/L
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
2/2 SYR4
Bromoform
14.479999999999995 µg/L
No EPA limit set
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
2/2 SYR4
Monochloroacetic Acid
13.2 µg/L
No EPA limit set
Highest in the city: RIALTO, CITY OF · 54,453 people · 2019
1/2 SYR4
Di(2-ethylhexyl) Phthalate
11 µg/L 183%
of the EPA limit, at the 95th percentile of samples — 6 µg/L
Highest in the city: RIALTO, CITY OF · 54,453 people · 2019
1/2 SYR4
Combined Uranium
10.653499999999996 µg/L 36%
of the EPA limit 30 µg/L
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
2/2 SYR4
Arsenic
9.2 µg/L 92%
of the EPA limit 10 µg/L
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
2/2 SYR4
Dibromoacetic Acid
8.239999999999995 µg/L
No EPA limit set
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
2/2 SYR4
Trichloroethylene
6.9 µg/L 138%
of the EPA limit, at the 95th percentile of samples — 5 µg/L
Highest in the city: RIALTO, CITY OF · 54,453 people · 2019
1/2 SYR4
Dichloroacetic Acid
6.675 µg/L
No EPA limit set
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
2/2 SYR4
Trichloroacetic Acid
4.814999999999999 µg/L
No EPA limit set
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
2/2 SYR4
Styrene
3.309999999999999 µg/L 3.3%
of the EPA limit 100 µg/L
Highest in the city: RIALTO, CITY OF · 54,453 people · 2019
1/2 SYR4
Chromium
3.1599999999999997 µg/L 3.2%
of the EPA limit 100 µg/L
Highest in the city: RIALTO, CITY OF · 54,453 people · 2019
1/2 SYR4
Dichloromethane
3.075 µg/L 62%
of the EPA limit 5 µg/L
Highest in the city: RIALTO, CITY OF · 54,453 people · 2019
1/2 SYR4
Xylenes, Total
1.995 µg/L 0%
of the EPA limit 10000 µg/L
Highest in the city: RIALTO, CITY OF · 54,453 people · 2019
1/2 SYR4
Gross Beta Particle Activity
1.728 pCi/L
No EPA limit set
Highest in the city: RIALTO, CITY OF · 54,453 people · 2016
1/2 SYR4
Monobromoacetic Acid
1.2899999999999998 µg/L
No EPA limit set
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
Highest in the city: 1.69 µg/L — RIALTO, CITY OF · 54,453 people · 2019
2/2 SYR4
Tetrachloroethylene
1.25 µg/L 25%
of the EPA limit 5 µg/L
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 people · 2019
2/2 SYR4
Ethylbenzene
1.233 µg/L 0.2%
of the EPA limit 700 µg/L
Highest in the city: RIALTO, CITY OF · 54,453 people · 2019
1/2 SYR4
1,2-Dichloropropane
0.9410 µg/L 19%
of the EPA limit 5 µg/L
Highest in the city: RIALTO, CITY OF · 54,453 people · 2019
1/2 SYR4
1,2-Dichloroethane
0.8000 µg/L 16%
of the EPA limit 5 µg/L
Highest in the city: RIALTO, CITY OF · 54,453 people · 2019
1/2 SYR4
1,1-Dichloroethylene
0.5750 µg/L 8.2%
of the EPA limit 7 µg/L
Highest in the city: RIALTO, CITY OF · 54,453 people · 2019
1/2 SYR4
1,2,4-Trichlorobenzene
0.5600 µg/L 0.8%
of the EPA limit 70 µg/L
Highest in the city: RIALTO, CITY OF · 54,453 people · 2019
1/2 SYR4
1,1,2-Trichloroethane
0.5600 µg/L 11%
of the EPA limit 5 µg/L
Highest in the city: RIALTO, CITY OF · 54,453 people · 2019
1/2 SYR4
1,2-DIBROMO-3-CHLOROPROPANE
0.0220 µg/L 11%
of the EPA limit 0.2000 µg/L
Highest in the city: RIALTO, CITY OF · 54,453 people · 2019
1/2 SYR4
Pfpea
0.0180 µg/L
No EPA limit set
Highest in the city: RIALTO, CITY OF · 54,453 people · 2024
1/2 UCMR-5
Pfhxa
0.0170 µg/L
No EPA limit set
Highest in the city: RIALTO, CITY OF · 54,453 people · 2024
1/2 UCMR-5
PFOA
0.0073 µg/L
No EPA limit set
Highest in the city: RIALTO, CITY OF · 54,453 people · 2024
1/2 UCMR-5
Pfba
0.0057 µg/L
No EPA limit set
Highest in the city: RIALTO, CITY OF · 54,453 people · 2024
1/2 UCMR-5
PFBS
0.0046 µg/L
No EPA limit set
Highest in the city: RIALTO, CITY OF · 54,453 people · 2024
1/2 UCMR-5
Pfhpa
0.0035 µg/L
No EPA limit set
Highest in the city: RIALTO, CITY OF · 54,453 people · 2024
1/2 UCMR-5
PFHXS
0.0035 µg/L
No EPA limit set
Highest in the city: RIALTO, CITY OF · 54,453 people · 2024
1/2 UCMR-5
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
Main supplier: WEST VALLEY WATER DISTRICT · 104,498 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 Rialto

SupplierPopulation served
WEST VALLEY WATER DISTRICT 104,498
RIALTO, CITY OF 54,453

Frequently asked questions about Rialto tap water

Is Rialto tap water safe to drink?

EPA testing detected 42 contaminants in the water serving Rialto. 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 Rialto?

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

What contaminants are in Rialto's water?

The contaminants EPA monitoring detected in Rialto include Nitrate-Nitrite, Nitrate, Fluoride, Copper, 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.