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Montana Water Quality
145
Utilities in database
0.7M
Residents served
48%
On private wells
2
Key contaminants tracked
Drinking Water in Montana
Montana has 145 community water systems serving approximately 0.7 million residents. Primary water sources include groundwater. The most commonly reported contaminants include disinfection byproducts, nitrates. 48% of Montana residents rely on private wells. MDEQ holds primary enforcement authority under the Safe Drinking Water Act.
Utilities in Montana
126–145 of 145Town of Sheridan
MT0000329 · 632 served
Greenfield Mobile Home Park
MT0000373 · 620 served
Town of Big Sandy
MT0000150 · 608 served
Hot Springs Municipal Water
MT0000251 · 600 served
Town of Belt
MT0000138 · 600 served
Town of Joliet
MT0000256 · 600 served
Cherry Creek Estates Llc
MT0004392 · 600 served
Ptarmigan Village Inc
MT0000133 · 600 served
Town of Medicine Lake
MT0000289 · 600 served
Countryside Village Mhp Grt Fls
MT0004830 · 600 served
Vaughn Cascade County Water and Sewer
MT0000352 · 585 served
Town of Wibaux
MT0000361 · 550 served
Windsor Estates
MT0003807 · 530 served
Two Buttes Water Users Assn
MT0000580 · 525 served
Wye Area Water System
MT0004107 · 512 served
Highland Park Utilities Assn
MT0000570 · 500 served
Gore Hill County Water Dist
MT0000232 · 500 served
Covered Wagon Mb Hm Park
MT0003810 · 500 served
Headquarters Apgar
MT0003176 · 500 served
Homestead Acres County Water and Sewer
MT0000526 · 500 served
Key Contaminant Concerns in Montana
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.
DBPs
When utilities add chlorine to water to kill pathogens, it reacts with dissolved organic matter — leaves, algae, soil — to produce disinfection byproducts (DBPs). Over 600 DBPs have been identified. The EPA regulates two groups: total trihalomethanes (TTHMs, including chloroform) and haloacetic acids (HAA5). DBP levels tend to be highest in surface water systems and in warm months when organic matter is elevated.
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Data source: Utility data from EPA SDWIS. 145 active community water systems ingested. CCR contaminant data ingestion in progress.
Last updated: 2026-04-23