Wyoming water quality
Wyoming has 735 active public water systems (1,852 on file total), 317 of them graded by TapGraded.
Grade distribution
Biggest water systems
CHEYENNE BOARD OF PUBLIC UTILITIES
CHEYENNE, WY · 64,165 served
CASPER, CITY OF
CASPER, WY · 59,000 served
LARAMIE, CITY OF
LARAMIE, WY · 32,395 served
GILLETTE, CITY OF
GILLETTE, WY · 32,222 served
JACKSON, TOWN OF
JACKSON, WY · 24,760 served
ROCK SPRINGS, CITY OF
ROCK SPRINGS, WY · 24,000 served
SHERIDAN, CITY OF
SHERIDAN, WY · 22,700 served
EVANSTON, CITY OF
EVANSTON, WY · 11,727 served
GREEN RIVER, CITY OF
GREEN RIVER, WY · 10,500 served
RIVERTON, CITY OF
RIVERTON, WY · 10,330 served
Lowest-graded systems
Active, graded systems serving at least 10,000 people, ordered by lowest Tap Grade first.
RIVERTON, CITY OF
RIVERTON, WY · 10,330 served
CHEYENNE BOARD OF PUBLIC UTILITIES
CHEYENNE, WY · 64,165 served
JACKSON, TOWN OF
JACKSON, WY · 24,760 served
SOUTH CHEYENNE WATER & SEWER DISTRICT
CHEYENNE, WY · 10,000 served
CODY, CITY OF
CODY, WY · 10,224 served
GILLETTE, CITY OF
GILLETTE, WY · 32,222 served
GREEN RIVER, CITY OF
GREEN RIVER, WY · 10,500 served
LARAMIE, CITY OF
LARAMIE, WY · 32,395 served
CASPER, CITY OF
CASPER, WY · 59,000 served
ROCK SPRINGS, CITY OF
ROCK SPRINGS, WY · 24,000 served
Source: EPA SDWIS/ECHO · Data as of 2026Q2