City of Chinook
EPA ID: MT0000174 · 1,300 people served · 2 ZIP codes
City of Chinook's current EPA file includes 4 unresolved violations — every outstanding finding is documented in federal records for this utility, which supplies water to approximately 1,300 residents across its service territory.
Data: EPA SDWIS Last verified: 2026-04-02
Service Area Map
Coverage area for City of Chinook Source: EPA SDWIS service area boundaries.
Service area boundary — Grade D
Service Area Demographics
The City of Chinook serves a community with a median household income of $57,887 and an estimated 2,336 residents across its service area. Approximately 91% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
Environmental Justice Note: 100% of the population in this service area is classified as disadvantaged under EPA's EJScreen criteria. Communities with higher disadvantaged populations often face disproportionate environmental and health burdens, including aging water infrastructure and limited resources for remediation.
🌊 Where Does Your Water Come From?
City of Chinook's water is drawn from rivers, lakes, or reservoirs. Surface water sources are more exposed to agricultural runoff, stormwater, and upstream discharges, but they typically receive more intensive treatment before reaching your tap.
About 3% of homes in Blaine County, Montana rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Infrastructure Risk
Detected Contaminants
How City of Chinook compares to EPA limits
What This Means For You
Total Trihalomethanes (TTHM) at 4 mg/L exceeds the EPA maximum of 0.08 mg/L. Bladder & rectal cancer risk; reproductive concerns. Consider granular activated carbon (GAC) filtration.
Surface Water Treatment Rule at 2 mg/L exceeds the EPA maximum of mg/L.
Total Trihalomethanes (TTHM) was detected in this water system. granular activated carbon (GAC) filtration can reduce exposure.
Find a certified water filter →Comparable Water Systems
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Estimated Remediation Costs
Average estimated costs across ZIP codes served by this system
Based on national averages for common remediation projects. Actual costs vary by property. Only issues flagged by EPA, FEMA, or state data for each ZIP code are included.
System Overview
City of Chinook (EPA ID: MT0000174) is a community water system in Montana that serves approximately 1,300 people from surface water sources.
This system provides water to 2 ZIP codes across 2 communities.
Average Home Safety Score: D (51/100)
Based on water quality violations, lead levels, and radon risk across all ZIP codes served by this system.
Violation History
Recent Violations
| Date | Contaminant | Type | Status |
|---|---|---|---|
| October 1, 2025 | Total Trihalomethanes (TTHM) | Health-based | Unresolved |
| July 1, 2025 | Total Trihalomethanes (TTHM) | Health-based | Unresolved |
| April 1, 2025 | Total Trihalomethanes (TTHM) | Health-based | Unresolved |
| January 1, 2025 | Total Trihalomethanes (TTHM) | Health-based | Unresolved |
| July 1, 2023 | Surface Water Treatment Rule | Monitoring | Resolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 4 | Yes |
| Surface Water Treatment Rule | Treatment Failure | 2 | No |
Health Risk Details
Total Trihalomethanes (TTHM) (EPA limit: 0.08 mg/L)
Bladder & rectal cancer risk; reproductive concerns At-risk groups: pregnant women, long-term consumers of chlorinated water, people who frequently shower in chlorinated water.
Removal methods: granular activated carbon (GAC), carbon block filter, point-of-entry aeration. Find the right filter →
Lead & Copper
EPA Lead and Copper Rule sampling data for ZIP codes served by this system:
| ZIP Code | Lead Level | Exceeds Limit | Sample Date |
|---|---|---|---|
| 59523 | 0.002 mg/L | No | N/A |
Radon Risk in Service Area
Dominant radon zone for ZIP codes served by this system: Zone 1 (High Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Need help with your water quality?
Typical cost: Water test: typically $20–$50 (DIY kit) · Professional inspection: $150–$400
Find the Right Water FilterFree tip: Let cold water run for 2 minutes before drinking — this helps flush lead from your pipes.
ZIP Codes Served
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for City of Chinook (MT0000174) on EPA.gov.
Frequently Asked Questions
Is City of Chinook water safe to drink?
City of Chinook has recorded 4 health-based violations in the past 5 years. While the system is required to treat water to meet federal standards, you may want to consider additional precautions such as a certified water filter.
How many people does City of Chinook serve?
City of Chinook serves approximately 1,300 people across 2 ZIP codes in Montana.
Where does City of Chinook get its water?
The primary water source is surface water.
Contact Your Water Utility
Public-record contact information for the water utility serving this system. Use these channels to request water quality reports, ask about service, or report issues directly.
Contact information from CHINOOK CITY OF Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility, does not act as its agent, and does not provide customer support for it. Contact details shown are public-record information from CCR filings. For service issues, contact the utility directly using the information above.
Water Source & Treatment
Where this water originates and how it's treated before reaching your tap.
Source: CHINOOK CITY OF Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility. Treatment and source data are sourced from the utility's published CCR filings.
Treatment regime
How this utility classifies its treatment process and what each reported treatment chemical does.
Treatment classification and chemical list sourced from CHINOOK CITY OF Consumer Confidence Report.
Treatment intensity is a ZipCheckup-derived classification based on the chemicals and processes the utility reports. Chemicals and contamination sources are taken verbatim from the utility's CCR filing. Routine federal monitoring and contaminant testing shown elsewhere on this page determine whether the water meets safety standards, not the treatment classification.
Lead Service Line Inventory
Service line breakdown reported under the federal Lead and Copper Rule Improvements (LCRI) inventory requirement:
Federal LCRI rule (effective October 2024) requires every public water system to inventory its service lines and complete lead-line replacement within 10 years.
Source: EPA SDWIS Federal Service Line Inventory (Phase 2) · Submitted 2026
ZipCheckup is not affiliated with the utility or state agency. Inventory figures render verbatim from the public LCRI submission cited above; ZipCheckup does not perform inspections or replacements.
Frequently Asked Questions
What You Can Do
Test your water
Home test kits can detect lead, bacteria, and other contaminants at your tap. Find the right filter →
Check your specific ZIP code
Water quality can vary within a system. View nearest ZIP report →
Contact your utility
City of Chinook (EPA ID: MT0000174) — request the latest Consumer Confidence Report or ask about specific contaminants.