Is Chinook, MT Tap Water Safe to Drink?
Graded B, with 4 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
77/100
waterverge.com Chinook, MT — Water Quality Report
Chinook's drinking water received a grade of B (77 out of 100), indicating good water quality. The city's 2 water systems serve approximately 1,400 residents using surface water.
Lead levels were measured at 0.0 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 31 violations on record, including 15 health-based violations. 4 remain unresolved.
What to know about Chinook's water
Chinook ranks #45 out of 115 cities in Montana for water quality, placing it mid-range 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, Chinook may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 6 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Chinook, MT water safe to drink?
Chinook's drinking water has significant quality concerns based on EPA testing data. With a grade of B (77/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 2 water systems serve approximately 1,400 residents using surface water (rivers, lakes, or reservoirs).
Recent water quality updates for Chinook
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Chinook's water quality assessment. Grade: B (77/100).
1 health-based. Contaminants: Total Haloacetic Acids (HAA5).
1 health-based. Contaminants: Total Haloacetic Acids (HAA5).
1 health-based. Contaminants: Total Haloacetic Acids (HAA5).
Federal disaster declaration (FEMA DR-4726). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-4388). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Chinook's water supply.
Well within EPA limits.
Violation history
Chinook's water system has 31 total violations on record, including 15 health-based violations. 4 remain unresolved. 6 violations were issued in the last 5 years.
Flood & environmental risk
Blaine County has experienced 5 federally declared disasters since 1986. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Lodge Creek Near Chinook, Battle Creek Near Chinook.
Where does Chinook's water come from?
Chinook's drinking water comes from surface water (rivers, lakes, or reservoirs), supplied by 2 water systems serving approximately 1,400 people. Surface water sources are more susceptible to contamination from runoff, industrial discharge, and algal blooms, requiring extensive treatment. Nearby water bodies include Lodge Creek Near Chinook (river), Battle Creek Near Chinook (river).
What Chinook residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Chinook's water.
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.
Chinook'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
Drought conditions
D2 — severe droughtBlaine County is currently in D2 (severe 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
Blaine County has experienced 5 federally declared disasters since 1986. 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. | 0.0 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Chinook compares by contaminant
Explore where Chinook ranks among all Montana cities for specific contaminants.
Water source & infrastructure
Where Chinook's water comes from
Chinook'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 1,400 people through 2 water systems.
Water bodies near Chinook
Chinook is located near 2 notable water bodies. As a surface water system, these water bodies may directly influence the city's drinking water supply.
Water systems serving Chinook
| System Name | PWSID | Population | Source |
|---|---|---|---|
| CHINOOK CITY OF | MT0000174 | 1,300 | SW |
| PERRYS WATER SERVICE | MT0004869 | 100 | SWP |
How Chinook compares
Full Montana rankings →Chinook's score of 77/100 is above the average of 45/100 among major Montana cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Montana rankings →About Chinook, MT
Learn more about your water
Guides and resources related to Chinook's water quality findings.
Explore water quality across Blaine
Frequently asked questions
Is Chinook, MT tap water safe to drink?
Chinook's water quality earned a grade of B (77/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #45 out of 115 cities tested in Montana.
What contaminants are in Chinook's water?
Lead was measured at 0.0 ppb (90th percentile). 31 violations are on record.
How is Chinook'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 Chinook?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Chinook's water come from?
Chinook's water is sourced from Surface water. The city has 2 water systems serving approximately 1,400 residents.
What health violations has Chinook's water system had?
Chinook has 15 health-based violations on record. The most recent violation was recorded in October 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 4 violations remain unresolved.
How does Chinook's water compare to other cities?
Chinook ranks #45 out of 115 cities in Montana (better than 61% of state cities) and #9137 out of 15744 cities nationally (42th percentile). The grade of B reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.