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Idaho Water Quality
174
Utilities in database
1.5M
Residents served
40%
On private wells
2
Key contaminants tracked
Drinking Water in Idaho
Idaho has 174 community water systems serving approximately 1.5 million residents. Primary water sources include groundwater. The most commonly reported contaminants include arsenic, nitrates. 40% of Idaho residents rely on private wells. DEQ holds primary enforcement authority under the Safe Drinking Water Act.
Utilities in Idaho
26–50 of 174City of Rathdrum
ID1280152 · 10,358 served
Burley Water Dept
ID5160008 · 10,345 served
Hayden Lake Irrigation Dist
ID1280087 · 9,375 served
Capitol Water Corp
ID4010022 · 9,000 served
Ross Point Water Dist
ID1280163 · 8,965 served
Avondale Irrigation Dist
ID1280008 · 8,785 served
University of Idaho
ID2290042 · 8,589 served
City of Payette
ID3380009 · 8,127 served
Hailey Water and Sewer
ID5070022 · 8,000 served
Mountain Home Air Force Base
ID4200054 · 7,500 served
City of Fruitland
ID3380005 · 7,135 served
City of Emmett
ID3230012 · 6,700 served
Eagle, City of (western Zone)
ID4010222 · 6,108 served
Central Shoshone County Water Dist
ID1400089 · 6,098 served
City of Rupert
ID5340017 · 5,796 served
City of Weiser
ID3440011 · 5,630 served
City of Preston
ID6210014 · 5,591 served
City of Rigby
ID7260032 · 5,400 served
City of Kimberly
ID5420033 · 5,359 served
City of American Falls
ID6390001 · 4,863 served
City of Buhl
ID5420007 · 4,518 served
City of Mccall
ID4430033 · 4,423 served
City of Shelley
ID6060071 · 4,409 served
City of St Maries
ID1050024 · 4,173 served
Hillside Service Area
ID1280095 · 4,140 served
Key Contaminant Concerns in Idaho
Nitrates
Nitrate (NO₃⁻) is a nitrogen-containing compound that forms naturally through the decomposition of organic matter. At elevated concentrations — almost always from human activity — nitrate interferes with the blood's ability to carry oxygen. The United States produces over 23 million tons of nitrogen fertilizer annually, making agricultural runoff the dominant source of nitrate contamination.
Arsenic
Arsenic (As) occurs naturally in rock and soil, dissolving into groundwater through natural weathering processes. Inorganic arsenic — the form found in drinking water — is a known human carcinogen. The western United States has particularly arsenic-rich geological formations, but elevated levels have been found in 48 states. Arsenic is tasteless and odorless.
Idaho Water FAQs
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Data source: Utility data from EPA SDWIS. 174 active community water systems ingested. CCR contaminant data ingestion in progress.
Last updated: 2026-04-22