State Hub
Montana Water Quality
145
Utilities in database
0.7M
Residents served
0
With open violations
36
PFAS monitored
Quick Answer
Montana public drinking water is served by 145 EPA-tracked water systems, providing service to approximately 0.7 million residents through public utilities. No open health-based violations are currently recorded across tracked systems in the EPA federal database. 36 systems have official PFAS monitoring records from the EPA UCMR 5 program (2023–2025). About 48% of MT residents use private wells, which fall outside federal utility compliance monitoring.
No open health-based violations are currently recorded in the EPA SDWIS database for Montana's tracked water systems. Always verify with your utility's Consumer Confidence Report for annual test results.
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.
Safest Large Utilities
Montana systems with no open health violations serving 10,000+ residents.
Utilities in Montana
76–100 of 145City of Chinook
MT0000174 · 1,300 served
Va Medical Center Helena
MT0000246 · 1,275 served
Black Eagle Cascade County Water Sewer
MT0000157 · 1,233 served
Lakeside Water System
MT0000266 · 1,225 served
Forest Park Water Rsid 24
MT0000233 · 1,200 served
Helena Leisure Llc
MT0000590 · 1,200 served
Hungry Horse Co Water and Sewer District
MT0000253 · 1,135 served
Town of Superior
MT0000339 · 1,100 served
Absarokee Water and Sewer Dist
MT0000003 · 1,100 served
Cmrwa Musselshell Judith Rural Water Sys
MT0005109 · 1,100 served
City of Harlowton
MT0000240 · 1,050 served
St Mary Headquarters and Cg
MT0002729 · 1,030 served
City of Scobey
MT0000326 · 1,026 served
City of White Sulphur Springs
MT0000360 · 1,000 served
Prairie Water Company
MT0003539 · 1,000 served
Town of Fairview
MT0000213 · 1,000 served
Meadow Lake Co Water and Sewer District
MT0000914 · 950 served
Westview Mobile Home Park
MT0000437 · 947 served
Pioneer Water Service
MT0004226 · 900 served
Town of Chester
MT0000173 · 870 served
Town of Darby
MT0000195 · 850 served
Valley Grove Subdivision
MT0003780 · 825 served
City of Harlem
MT0000239 · 820 served
Phantom Hills Water System
MT0004379 · 810 served
Worden Ballantine Yellowstone
MT0000022 · 800 served
Key Contaminant Concerns in Montana
These contaminants appear most frequently in Montana utility records or pose elevated risk in this region based on EPA data.
Nitrates
Nitrate (NO₃⁻) is a nitrogen-containing compound that forms naturally through the decomposition of organic matter. At elevated concentrations — almost always caused by human activity — nitrate is converted in the digestive system to nitrite, which then reacts with hemoglobin to form methemoglobin, a form of hemoglobin that cannot carry oxygen. In the body, nitrite also reacts with amines in food to form N-nitroso compounds (nitrosamines) — known carcinogens classified by the IARC as Group 2A (probable human carcinogens). The United States applies over 23 million tons of nitrogen fertilizer annually, making agricultural runoff the dominant source of nitrate contamination in U.S. groundwater.
EPA limit: 10 mg/L
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.
EPA limit: 80 µg/L (TTHMs) / 60 µg/L (HAA5)
City Water Reports in Montana
Tap water quality pages for Montana cities — violations, PFAS records, utility profiles, and official source links.
Independent Water Testing
Find a certified lab in Montana
Utility compliance records show what water systems report to the EPA. An independent test from a certified laboratory confirms what's actually in your tap water. Montana labs can test for PFAS, lead, nitrates, bacteria, and dozens of other contaminants.
Explore Water Quality in Montana
City of Chinook
Violation history, PFAS records, and official source links
Va Medical Center Helena
Violation history, PFAS records, and official source links
Black Eagle Cascade County Water Sewer
Violation history, PFAS records, and official source links
PFAS monitoring records — Montana
36 water systems in Montana with EPA UCMR 5 records
Lead in Montana drinking water
State-specific lead data, violation utilities, and testing guidance
PFAS in Montana drinking water
State-specific PFAS data, MCL context, and treatment options
Certified water testing labs in Montana
Labs certified for PFAS (EPA 533/537.1), lead, and bacteria testing
Water treatment options
Reverse osmosis, activated carbon, and filtration guides with cost ranges
Data sources and methodology
How WaterUtilityReport.com sources and validates official EPA data
Common Questions About Montana Drinking Water
Does Montana drinking water have PFAS?
36 Montana water systems have EPA UCMR 5 PFAS monitoring records (2023–2025)
Which Montana water utilities have open violations?
Browse Montana utility compliance records and violation history
How do I test my water in Montana?
State-certified labs for PFAS (EPA 533/537.1), lead, nitrate, and bacteria testing
What treatment removes PFAS from MT tap water?
Reverse osmosis removes PFAS, lead, arsenic, and nitrates — cost, maintenance, and NSF certification explained
What do Montana PFAS records tell me about my water?
EPA limits, health context, and what UCMR 5 detection above MRL means for your water
How is Montana water quality data sourced here?
EPA SDWIS violations, UCMR 5 PFAS records, and CCR data — sources, accuracy notes, and limitations
Montana Water FAQs
Data sources: Utility compliance and violation data from EPA SDWIS (Safe Drinking Water Information System). PFAS monitoring records from EPA UCMR 5 (Unregulated Contaminant Monitoring Rule 5, 2023–2025). Contaminant data from EPA and ATSDR public references. This page summarizes public records — it is not a compliance determination. Methodology →
Last updated: 2026-04-23