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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
101–125 of 174City of Ashton
ID7220004 · 1,129 served
Dry Creek Water Company Llc
ID4010266 · 1,125 served
City of Moyie Springs
ID1110021 · 1,123 served
Remington Rec Water Dist
ID1280270 · 1,104 served
Caldwell Housing Authority
ID3140012 · 1,100 served
City of Arco
ID6120001 · 1,080 served
City of Genesee
ID2290015 · 1,044 served
City of Plummer
ID1050021 · 1,034 served
Black Rock Utilities Inc
ID1280290 · 1,014 served
City of Franklin
ID6210007 · 1,000 served
City of Cascade
ID4430012 · 1,000 served
Carey Water and Sewer
ID5070010 · 993 served
City of Athol
ID1280006 · 990 served
City of Hagerman
ID5240012 · 988 served
Greenferry Water & Sewer District
ID1280077 · 978 served
Cottonwood Water Dept
ID2250013 · 977 served
Schweitzer Basin Water Company
ID1090124 · 955 served
Stoneridge Utilities
ID1090009 · 940 served
Teton Springs Water and Sewer Company
ID7410033 · 924 served
City of Grace
ID6150010 · 920 served
City of Challis
ID7190013 · 900 served
City of Council
ID3020002 · 900 served
City of Hazelton
ID5270007 · 899 served
City of Dover
ID1090193 · 865 served
City of Troy
ID2290041 · 850 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.
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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