Montana water quality
Montana has 2,221 active public water systems (4,728 on file total), 818 of them graded by TapGraded.
Grade distribution
Biggest water systems
BILLINGS CITY OF
BILLINGS, MT · 114,000 served
MISSOULA WATER
MISSOULA, MT · 68,200 served
GREAT FALLS CITY OF
GREAT FALLS, MT · 60,000 served
BOZEMAN CITY OF
BOZEMAN, MT · 56,000 served
BUTTE SILVERBOW WATER DEPT
BUTTE, MT · 33,000 served
HELENA WATER SYSTEM
HELENA, MT · 32,091 served
KALISPELL PUBLIC WORKS
KALISPELL, MT · 25,000 served
MONTANA STATE UNIVERSITY BOZEMAN
BOZEMAN, MT · 19,200 served
UNIVERSITY OF MONTANA
MISSOULA, MT · 15,000 served
BILLINGS HEIGHTS CO WATER DIST OF
BILLINGS, MT · 12,000 served
Lowest-graded systems
Active, graded systems serving at least 10,000 people, ordered by lowest Tap Grade first.
HELENA WATER SYSTEM
HELENA, MT · 32,091 served
KALISPELL PUBLIC WORKS
KALISPELL, MT · 25,000 served
GREAT FALLS CITY OF
GREAT FALLS, MT · 60,000 served
BILLINGS CITY OF
BILLINGS, MT · 114,000 served
BILLINGS HEIGHTS CO WATER DIST OF
BILLINGS, MT · 12,000 served
BUTTE SILVERBOW WATER DEPT
BUTTE, MT · 33,000 served
MISSOULA WATER
MISSOULA, MT · 68,200 served
BOZEMAN CITY OF
BOZEMAN, MT · 56,000 served
BELGRADE CITY OF
BELGRADE, MT · 10,460 served
WHITEFISH CITY OF
WHITEFISH, MT · 10,418 served
Source: EPA SDWIS/ECHO · Data as of 2026Q2