COLSTRIP, Montana Tap Water Quality

2,350 people served · 1 water system

Poor

COLSTRIP, Montana is a small town with 2,350 residents served by a single public water system. Water service covers ZIP code 59323.

COLSTRIP has a notable pattern of EPA health-based violations across multiple compliance periods. Filtered water is a reasonable precaution while the utility implements long-term corrective action.

EPA reporting identifies Total Trihalomethanes (TTHMs) and Coliform Bacteria among the regulated contaminants associated with COLSTRIP's recent health-based violations. Each contaminant has different sources, health implications, and recommended mitigation steps — links to the full EPA reference for each are listed alongside the violation history below.

Last updated: 2026-05-18 · Source: EPA SDWIS

Location

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Centered on ZIP-code centroids of water systems serving this city.

ZIP Codes Served

59323

Health-Based Violations (Last 5 Years)

EPA Maximum Contaminant Level exceedances reported by water systems serving COLSTRIP. Each entry explains the contaminant, the health risk, and recommended precautions, and links to a full guide.

Total Trihalomethanes (TTHMs)disinfectant

EPA Code 2950 · Maximum Contaminant Level Exceedance

violations

EPA Limit

0.08 mg/L

Last Reading

81 UG/L

First Reported

Jul 2024

Most Recent

Jul 2024

What this violation means

Total Trihalomethanes (TTHMs) form when chlorine reacts with naturally occurring organic matter — leaves, soil, algae — in source water. They are among the most commonly reported violations because utilities pulling from surface water (rivers, lakes, reservoirs) struggle to balance disinfection with byproduct formation. Long-term exposure has been linked to bladder cancer and adverse pregnancy outcomes.

Recommended precautions

→Activated carbon filters (pitcher, faucet, or under-sink) effectively reduce TTHMs.
→Letting water sit uncovered allows TTHMs to off-gas — leave a pitcher in the fridge for several hours.
→Shower with the bathroom fan on; TTHMs can volatilize into the air during hot showers.
→Boiling reduces TTHMs through volatilization, but only after extended boiling.

Read the complete guide to Total Trihalomethanes (TTHMs)

Coliform Bacteriamicrobial

EPA Code 0200 · Treatment Technique Violation

violations

EPA Limit

0 per 100 mL presence/absence

Last Reading

—

First Reported

Jul 2024

Most Recent

Jul 2024

What this violation means

Total coliform bacteria are themselves usually harmless, but their presence signals that the water distribution system has a vulnerability — typically a cracked pipe, loss of pressure, or back-siphonage — that could allow disease-causing pathogens to enter. Repeated coliform-positive samples trigger mandatory utility investigation.

Recommended precautions

→If your utility issues a boil-water advisory, boil all drinking and cooking water for at least one minute.
→Use bottled water until the advisory is lifted.
→Ice from icemakers and beverages made before the advisory should be discarded.
→UV light and chlorination both kill coliform bacteria — most home filters do not.

Read the complete guide to Coliform Bacteria

Source: EPA Safe Drinking Water Information System (SDWIS). Health-based violations only. Older violations may have been resolved; check your utility's most recent Consumer Confidence Report for current status.

Water Systems Serving COLSTRIP

COLSTRIP CITY OF

PWSID: MT0000180

2,350 served

7 violations

What Can You Do?

✅ Request your utility's annual Consumer Confidence Report (CCR) — required by law.
✅ Use an NSF-certified water filter if violations involve lead, arsenic, or PFAS.
✅ Run cold water for 30 seconds before drinking if you have older plumbing (reduces lead).
✅ Check back monthly — we update data from the EPA every 30 days.

About this data

This overview reflects EPA SDWIS data published as of 2026-05-18. It covers active Community Water Systems (CWS) that exceeded federal Maximum Contaminant Levels during the past five-year EPA reporting window. For up-to-the-minute information, request a current Consumer Confidence Report from your utility, or review the EPA's public dashboard.

Frequently Asked Questions

Is COLSTRIP, Montana tap water safe to drink?▼

This city's water had significant EPA violations in the last 5 years.

How many EPA violations does COLSTRIP have?▼

COLSTRIP has 7 EPA health-based water violations in the last 5 years across 1 water system serving 2,350 people.

What contaminants have been found in COLSTRIP water?▼

The following EPA-regulated contaminants have been detected: 2950, 0200. View details about each contaminant, health effects, and recommended precautions above in the violations table.

Should I use a water filter in COLSTRIP?▼

Using an NSF-certified water filter is recommended if your area has violations involving lead, arsenic, or PFAS. For other contaminants, consult your local water utility. Check the annual Consumer Confidence Report (CCR) for detailed guidance.

What should I do if there are violations in COLSTRIP?▼

Request your water utility's annual Consumer Confidence Report (CCR), which is required by the EPA. Follow the utility's guidance on boil water advisories. Run cold water for 30 seconds before drinking if you have older plumbing. Use an NSF-certified filter if needed based on your water system's violations.