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Tap water quality report

Twin Falls, ID

EPA monitoring detected 14 contaminants across the 2 water suppliers serving Twin Falls. 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
56,261
people served
14
contaminants found
Idaho rankings Lead in Idaho PFAS in Idaho

What was found in Twin Falls'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
4070 µg/L 41%
of the EPA limit 10000 µg/L
Main supplier: TWIN FALLS CITY OF · 56,121 people · 2019
Highest in the city: 7992.5 µg/L — MEANDER POINT SUBD · 140 people · 2019
2/2 SYR4
Nitrate-Nitrite
4737 µg/L 47%
of the EPA limit 10000 µg/L
Main supplier: TWIN FALLS CITY OF · 56,121 people · 2012
1/2 SYR4
Fluoride
961 µg/L 24%
of the EPA limit 4000 µg/L
Main supplier: TWIN FALLS CITY OF · 56,121 people · 2012
2/2 SYR4
Barium
63.07 µg/L 3.2%
of the EPA limit 2000 µg/L
Main supplier: TWIN FALLS CITY OF · 56,121 people · 2012
Highest in the city: 130 µg/L — MEANDER POINT SUBD · 140 people · 2018
2/2 SYR4
Lithium
47.7 µg/L
No EPA limit set
Main supplier: TWIN FALLS CITY OF · 56,121 people · 2025
1/2 UCMR-5
TTHM
40.36 µg/L 50%
of the EPA limit 80 µg/L
Main supplier: TWIN FALLS CITY OF · 56,121 people · 2019
2/2 SYR4
Combined Uranium
5.7 µg/L 19%
of the EPA limit 30 µg/L
Main supplier: TWIN FALLS CITY OF · 56,121 people · 2019
Highest in the city: 22.38 µg/L — MEANDER POINT SUBD · 140 people · 2018
2/2 SYR4
Arsenic
12.01 µg/L 120%
of the EPA limit, at the 95th percentile of samples — 10 µg/L
Main supplier: TWIN FALLS CITY OF · 56,121 people · 2019
Highest in the city: 14.19 µg/L — MEANDER POINT SUBD · 140 people · 2019
2/2 SYR4
Total Haloacetic Acids (HAA5)
8.42 µg/L 14%
of the EPA limit 60 µg/L
Main supplier: TWIN FALLS CITY OF · 56,121 people · 2019
2/2 SYR4
Gross Alpha, Excl. Radon And U
0.6000 pCi/L 4%
of the EPA limit 15 pCi/L
Main supplier: TWIN FALLS CITY OF · 56,121 people · 2019
Highest in the city: 4.5 pCi/L — MEANDER POINT SUBD · 140 people · 2015
2/2 SYR4
Selenium
2.384 µg/L 4.8%
of the EPA limit 50 µg/L
Main supplier: TWIN FALLS CITY OF · 56,121 people · 2012
2/2 SYR4
Chromium
2.061 µg/L 2.1%
of the EPA limit 100 µg/L
Main supplier: TWIN FALLS CITY OF · 56,121 people · 2012
1/2 SYR4
Combined Radium (-226 And -228)
1.4 pCi/L 28%
of the EPA limit 5 pCi/L
Main supplier: TWIN FALLS CITY OF · 56,121 people · 2019
1/2 SYR4
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
Main supplier: TWIN FALLS CITY OF · 56,121 people · 2026
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 Twin Falls

SupplierPopulation served
TWIN FALLS CITY OF 56,121
MEANDER POINT SUBD 140

Frequently asked questions about Twin Falls tap water

Is Twin Falls tap water safe to drink?

EPA testing detected 14 contaminants in the water serving Twin Falls. 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 Twin Falls?

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

What contaminants are in Twin Falls's water?

The contaminants EPA monitoring detected in Twin Falls include Nitrate, Nitrate-Nitrite, Fluoride, Barium, Lithium. 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.