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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
151–174 of 174Kooskia Water Dept
ID2250032 · 607 served
Taylor Mountain Water and Sewer District
ID7100023 · 600 served
City of Worley
ID1280206 · 591 served
Kingston Water Dist 1
ID1400030 · 585 served
City of New Meadows
ID3020012 · 582 served
Fernwood Water Dist
ID1050011 · 580 served
City of Mackay
ID7190032 · 566 served
Chilco Service Area
ID1280048 · 563 served
Meadows at West Mountain
ID4430103 · 550 served
Syringa Heights Water Dist
ID1090136 · 550 served
West Bonner Water Dist 1
ID1090151 · 545 served
Rustic Acres Mobile Home Park
ID4010126 · 540 served
City of Notus
ID3140083 · 539 served
City of Paris
ID6040022 · 535 served
Bee Line Water Assn Inc
ID1110001 · 533 served
City of Deary
ID2290008 · 529 served
Wilderness Ranch Owners Association Inc
ID4080055 · 525 served
City of Dubois
ID7170003 · 511 served
City of Firth
ID6060016 · 511 served
City of Dayton
ID6210004 · 510 served
City of Richfield
ID5320005 · 501 served
City of Craigmont
ID2310001 · 501 served
Pine Villa Park and Water Assn
ID1280142 · 500 served
Oakley Valley Water Corporation
ID5160031 · 500 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