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Tap water quality report

Thermal, CA

EPA monitoring detected 8 contaminants across the 17 water suppliers serving Thermal. 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.

17
water suppliers
2,291
people served
8
contaminants found
California rankings Lead in California PFAS in California

What was found in Thermal'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
5500 µg/L 55%
of the EPA limit 10000 µg/L
Main supplier: Oasis Mobile Home Park · 826 people · 2019
Highest in the city: 7280 µg/L — Torres-Martinez Avenue 64 · 110 people · 2019
3/17 SYR4
Fluoride
6320 µg/L 158%
of the EPA limit, at the 95th percentile of samples — 4000 µg/L
Highest in the city: DD Mobile Home Park · 275 people · 2019
3/17 SYR4
Arsenic
94.15 µg/L 942%
of the EPA limit, at the 95th percentile of samples — 10 µg/L
Main supplier: Oasis Mobile Home Park · 826 people · 2019
3/17 SYR4
Barium
68 µg/L 3.4%
of the EPA limit 2000 µg/L
Highest in the city: Torres-Martinez Avenue 64 · 110 people · 2015
2/17 SYR4
Chromium
15 µg/L 15%
of the EPA limit 100 µg/L
Highest in the city: AMEZCUA - GARCIA WATER · 170 people · 2018
2/17 SYR4
TTHM
4.47 µg/L 5.6%
of the EPA limit 80 µg/L
Main supplier: Oasis Mobile Home Park · 826 people · 2015
Highest in the city: 4.7 µg/L — Torres-Martinez Avenue 64 · 110 people · 2017
3/17 SYR4
Combined Uranium
1.11005 µg/L 3.7%
of the EPA limit 30 µg/L
Main supplier: Oasis Mobile Home Park · 826 people · 2013
1/17 SYR4
Lead
0.0010 mg/L 6.7%
of the EPA limit 0.0150 mg/L
Main supplier: Oasis Mobile Home Park · 826 people · 2025
Highest in the city: 0.0050 mg/L — Toledo MHP · 68 people · 2025
17/17 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 Thermal

SupplierPopulation served
Oasis Mobile Home Park 826
Torres-Martinez Clinic 379
DD Mobile Home Park 275
AMEZCUA - GARCIA WATER 170
Torres-Martinez Avenue 64 110
Montano Ranch 72
Toledo MHP 68
Ramon Zaragoza Water 51
Gamez MHP 48
El Mesquite MHP 48
Castro Ranch 44
Gonzalez MHP 41
Ranchos Los Ferro MHP 41
Sandoval MHP 38
Arellano MHP 30
Garcia MHP 25
Barajas MHP 25

Frequently asked questions about Thermal tap water

Is Thermal tap water safe to drink?

EPA testing detected 8 contaminants in the water serving Thermal. 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 Thermal?

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

What contaminants are in Thermal's water?

The contaminants EPA monitoring detected in Thermal include Nitrate, Fluoride, Arsenic, Barium, Chromium. 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.