South Dakota water quality
South Dakota has 709 active public water systems (1,688 on file total), 513 of them graded by TapGraded.
Grade distribution
Biggest water systems
SIOUX FALLS
SIOUX FALLS, SD · 216,462 served
RAPID CITY
RAPID CITY, SD · 72,009 served
ABERDEEN
ABERDEEN, SD · 27,989 served
BROOKINGS MUNICIPAL UTILITIES
BROOKINGS, SD · 23,377 served
WATERTOWN MUNICIPAL UTILITIES
WATERTOWN, SD · 23,230 served
WEB WATER DEVELOPMENT ASSOCIATION
ABERDEEN, SD · 20,750 served
MITCHELL
MITCHELL, SD · 15,651 served
YANKTON
YANKTON, SD · 15,411 served
HURON
HURON, SD · 14,263 served
PIERRE
PIERRE, SD · 14,091 served
Lowest-graded systems
Active, graded systems serving at least 10,000 people, ordered by lowest Tap Grade first.
ABERDEEN
ABERDEEN, SD · 27,989 served
BOX ELDER
BOX ELDER, SD · 14,000 served
RAPID VALLEY SANITARY DISTRICT
RAPID CITY, SD · 11,408 served
RAPID CITY
RAPID CITY, SD · 72,009 served
BROOKINGS MUNICIPAL UTILITIES
BROOKINGS, SD · 23,377 served
HURON
HURON, SD · 14,263 served
BRANDON
BRANDON, SD · 11,048 served
MITCHELL
MITCHELL, SD · 15,651 served
SIOUX FALLS
SIOUX FALLS, SD · 216,462 served
WATERTOWN MUNICIPAL UTILITIES
WATERTOWN, SD · 23,230 served
Cities in South Dakota
Source: EPA SDWIS/ECHO · Data as of 2026Q2