Is Colstrip, MT Tap Water Safe to Drink?
Graded A-, with 2 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
85.2/100
waterverge.com Colstrip, MT — Water Quality Report
Colstrip's drinking water received a grade of A- (85.2 out of 100), indicating good water quality. The city's 1 water system serves approximately 2,350 residents using surface water.
Lead levels were measured at 1.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 56 violations on record, including 2 health-based violations. 2 remain unresolved.
What to know about Colstrip's water
Colstrip ranks #18 out of 115 cities in Montana for water quality, placing it above average in the state.
The city draws from surface water sources, which are more susceptible to seasonal runoff and agricultural contamination, requiring extensive multi-barrier treatment including coagulation, filtration, and disinfection.
As a small community water system, Colstrip may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 8 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Colstrip, MT water safe to drink?
Colstrip's tap water meets most EPA standards but has areas that warrant attention. With a grade of A- (85.2/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 2,350 residents using surface water (rivers, lakes, or reservoirs).
Recent water quality updates for Colstrip
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Colstrip's water quality assessment. Grade: A- (85.2/100).
2 health-based. Contaminants: TTHM, Surface Water Treatment Rule.
Contaminants: Surface Water Treatment Rule.
Contaminants: Total Haloacetic Acids (HAA5), TTHM.
Federal disaster declaration (FEMA DR-4172). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-4127). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Colstrip's water supply.
Well within EPA limits.
Violation history
Colstrip's water system has 56 total violations on record, including 2 health-based violations. 2 remain unresolved. 8 violations were issued in the last 5 years.
Flood & environmental risk
Rosebud County has experienced 5 federally declared disasters since 1978. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies.
Where does Colstrip's water come from?
Colstrip's drinking water comes from surface water (rivers, lakes, or reservoirs), supplied by 1 water system serving approximately 2,350 people. Surface water sources are more susceptible to contamination from runoff, industrial discharge, and algal blooms, requiring extensive treatment.
What Colstrip residents can do
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Colstrip's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Top industrial polluters within 10 miles of Colstrip
Industrial polluters nearby
Reported releases to surface water by facilities near Colstrip, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
COLSTRIP STEAM ELECTRIC STATION COLSTRIP, MT59323 | — | — | 0.8 mi |
COLSTRIP ENERGY LP ROSEBUD POWER PLANT COLSTRIP, MT59323 | — | — | 5.6 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Drought conditions
D1 — moderate droughtRosebud County is currently in D1 (moderate drought) per the U.S. Drought Monitor (week of May 5, 2026). Drought can elevate disinfection-byproduct (TTHM/HAA5) levels and taste/odor issues as utilities draw from lower reservoirs.
Source: U.S. Drought Monitor, updated weekly by NDMC, USDA, and NOAA.
Flood & disaster history
Rosebud County has experienced 5 federally declared disasters since 1978. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 1.0 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Colstrip compares by contaminant
Explore where Colstrip ranks among all Montana cities for specific contaminants.
Water source & infrastructure
Where Colstrip's water comes from
Colstrip's drinking water comes primarily from surface water sources such as rivers, lakes, or reservoirs.
Surface water systems require multi-stage treatment including coagulation, sedimentation, filtration, and disinfection to meet EPA Safe Drinking Water Act standards.
These sources can be impacted by seasonal changes, stormwater runoff, upstream agriculture, and industrial discharge.
The system is operated by local government ownership and serves approximately 2,350 people through 1 water system.
Water systems serving Colstrip
| System Name | PWSID | Population | Source |
|---|---|---|---|
| COLSTRIP CITY OF | MT0000180 | 2,350 | SW |
How Colstrip compares
Full Montana rankings →Colstrip's score of 85.2/100 is above the average of 45/100 among major Montana cities. It outscores 10 of 10 nearby cities.
Nearby cities
View Montana rankings →About Colstrip, MT
Wikipedia →Colstrip is a city in Rosebud County, Montana, United States. The population was 2,096 at the 2020 census.
Learn more about your water
Guides and resources related to Colstrip's water quality findings.
Explore water quality across Rosebud
Frequently asked questions
Is Colstrip, MT tap water safe to drink?
Colstrip's water quality earned a grade of A- (85.2/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #18 out of 115 cities tested in Montana.
What contaminants are in Colstrip's water?
Lead was measured at 1.0 ppb (90th percentile). 56 violations are on record.
How is Colstrip's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Colstrip?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Colstrip's water come from?
Colstrip's water is sourced from Surface water. The city has 1 water system serving approximately 2,350 residents.
What health violations has Colstrip's water system had?
Colstrip has 2 health-based violations on record. The most recent violation was recorded in July 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 2 violations remain unresolved.
How does Colstrip's water compare to other cities?
Colstrip ranks #18 out of 115 cities in Montana (better than 84% of state cities) and #5454 out of 15744 cities nationally (65th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Colstrip's small water system affect quality?
Colstrip's system serves approximately 2,350 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 56 violations on record.