TapWaterGuide
Worldwide water safety reference
United States Last reviewed:

Montana Tap Water Quality

about 730
Community water systems
City reports on this site
3
Tracked contaminants
August 28, 2026
Data reviewed

Check a Montana ZIP Code

Overview

Montana's cities drink well: Bozeman and Missoula use mountain snowmelt and clean valley aquifers, Billings treats Yellowstone River water, and the major systems meet all federal standards. Missoula's aquifer is among the most productive and pristine urban sources in the West.

The state's mining century left its mark: Butte's Berkeley Pit is America's most infamous acid-mine lake (isolated from drinking supplies, but emblematic), and legacy metals affect some streams and private wells near historic districts. Naturally occurring arsenic tracks the Madison and Missouri River systems downstream of Yellowstone's geothermal basins.

Common Contaminants in Montana

Arsenic

Geothermally sourced arsenic in the Madison/Missouri drainage affects some systems and wells; treated where needed

Mining-legacy metals

Copper, zinc, and arsenic near historic districts (Butte, Anaconda) affect surface water and some private wells, not compliant public systems

Nitrate and bacteria in wells

Rural private wells, common across the state, need routine testing

Violations & Compliance

Public-system compliance is solid; most violations are monitoring lapses in very small systems. Superfund work around Butte and Anaconda addresses the mining legacy separately from drinking-water systems.

City Reports for Montana

We haven't published individual city water reports for Montana yet. Use the ZIP lookup for a statewide assessment, and check your utility's annual Consumer Confidence Report for local detail.

Frequently Asked Questions

Sources & References

The safety rating and guidance on this page draw on the following sources. See our full methodology.