| Public water system | Population served |
|---|---|
| DES MOINES WATER WORKS | 246,055 |
| CEDAR RAPIDS WATER DEPARTMENT | 142,364 |
| SIOUX CITY WATER SUPPLY | 85,791 |
| ANKENY, CITY OF | 76,207 |
| WEST DES MOINES WATER WORKS | 73,959 |
| WATERLOO WATER WORKS | 69,504 |
| IOWA CITY WATER DEPARTMENT | 68,753 |
| COUNCIL BLUFFS WATER WORKS | 64,447 |
| DUBUQUE WATER WORKS | 59,667 |
| AMES WATER TREATMENT PLANT | 55,177 |
| URBANDALE WATER UTILITY | 45,605 |
| ISU | 42,000 |
| MARION MUNICIPAL WATER DEPT | 41,623 |
| CEDAR FALLS MUNICIPAL WATER UTILITIES | 40,713 |
| WAUKEE WATER SUPPLY | 31,823 |
| MARSHALLTOWN WATER WORKS | 27,680 |
| MASON CITY WATER DEPARTMENT | 27,338 |
| UNIVERSITY WATER SYSTEM | 26,684 |
| BURLINGTON MUNICIPAL WATERWORKS | 26,015 |
| FORT DODGE WATER SUPPLY | 25,874 |
| OTTUMWA WATER WORKS | 25,529 |
| MUSCATINE POWER & WATER | 25,516 |
| JOHNSTON MUNICIPAL WATER SUPPLY | 24,897 |
| NORTH LIBERTY WATER SUPPLY | 23,276 |
| CORALVILLE MUNI WATER SYSTEM | 22,318 |
| CLIVE WATER DEPARTMENT | 20,277 |
| ALTOONA WATER SUPPLY | 19,565 |
| GRIMES WATER SUPPLY | 17,809 |
| NEWTON WATER SUPPLY | 16,518 |
| INDIANOLA WATER SUPPLY | 15,833 |
| NORWALK WATER SUPPLY | 14,334 |
| OSKALOOSA MUNICIPAL WATER DEPT | 12,808 |
| BOONE WATER WORKS | 12,704 |
| STORM LAKE WATER TREATMENT PLANT | 11,431 |
| SPENCER MUNICIPAL WATER UTILITY | 11,325 |
| FT MADISON MUNI WATER WORKS | 11,087 |
| PELLA WATER WORKS DEPARTMENT | 11,052 |
| LEMARS WATER DEPARTMENT | 10,606 |
| WAVERLY WATER DEPARTMENT | 10,394 |
| CARROLL MUNICIPAL WATER SUPPLY | 10,184 |
| KEOKUK MUNICIPAL WATER WORKS | 9,900 |
| FAIRFIELD WATER SUPPLY | 9,821 |
| GRINNELL WATER DEPARTMENT | 9,564 |
| BONDURANT MUNI WATER SUPPLY | 9,393 |
| DENISON WATER SUPPLY | 9,381 |
| MOUNT PLEASANT MUNICIPAL UTILITIES | 9,274 |
| KNOXVILLE WATER WORKS | 8,400 |
| SIOUX CENTER MUNICIPAL WATER DEPARTMENT | 8,231 |
| PERRY MUNICIPAL WATER WORKS | 7,836 |
| WEBSTER CITY WATER SUPPLY | 7,825 |
| CLEAR LAKE WATER DEPARTMENT | 7,687 |
| DECORAH WATER DEPARTMENT | 7,615 |
| TIFFIN WATER SUPPLY | 7,577 |
| CRESTON WATER SUPPLY | 7,536 |
| CHARLES CITY WATER SUPPLY | 7,446 |
| WASHINGTON WATER DEPARTMENT | 7,362 |
| ATLANTIC MUNICIPAL UTILITIES | 7,252 |
| HIAWATHA WATER DEPT | 7,183 |
| NEVADA WATER SUPPLY | 6,925 |
| ELDRIDGE WATER SUPPLY | 6,726 |
| POLK CITY WATER SUPPLY | 6,533 |
| ADEL MUNICIPAL WATER WORKS | 6,461 |
| ORANGE CITY MUNICIPAL WATER DEPARTMENT | 6,267 |
| SPIRIT LAKE WATERWORKS | 6,167 |
| MAQUOKETA MUNICIPAL WATER | 6,128 |
| INDEPENDENCE WATER DEPT | 6,064 |
| ASBURY MUNICIPAL WATER SYSTEM | 5,943 |
| OELWEIN MUNICIPAL WATER WORKS | 5,920 |
| ESTHERVILLE WATER TREATMENT PLANT | 5,904 |
| RED OAK WATER SUPPLY | 5,596 |
| DE WITT WATER SUPPLY | 5,514 |
| SHELDON WATER DEPARTMENT | 5,512 |
| OSCEOLA WATER WORKS | 5,503 |
| ALGONA MUNICIPAL UTILITIES | 5,487 |
| GLENWOOD MUNICIPAL UTILITIES | 5,449 |
| WINTERSET MUNICIPAL WATERWORKS | 5,428 |
| CENTERVILLE MUNICIPAL WATERWORKS | 5,344 |
| CHEROKEE WATER SUPPLY - PLANT 1 | 5,199 |
| IOWA FALLS WATER DEPARTMENT | 5,146 |
| MANCHESTER WATER SUPPLY | 5,077 |
| HARLAN MUNICIPAL UTILITIES | 5,067 |
| SERGEANT BLUFF WATER SUPPLY | 5,015 |
| VINTON MUNICIPAL WATER DEPT | 4,938 |
| SHENANDOAH WATER DEPT | 4,925 |
| HUMBOLDT MUNICIPAL WATER DEPT | 4,792 |
| CAMANCHE WATER SUPPLY | 4,570 |
| EVANSDALE WATER WORKS | 4,561 |
| MOUNT VERNON WATER SUPPLY | 4,527 |
| DYERSVILLE MUNICIPAL WATER CO | 4,477 |
| ANAMOSA MUNICIPAL WATER SUPPLY | 4,457 |
| CHARITON MUNICIPAL WATER WORKS | 4,381 |
| CLARINDA WATER PLANT | 4,372 |
| HAMPTON MUNI WATER WORKS | 4,337 |
| FOREST CITY WATER SUPPLY | 4,285 |
| HUXLEY WATERWORKS DEPT | 4,244 |
| JEFFERSON WATER DEPARTMENT | 4,182 |
| CARLISLE WATER SUPPLY | 4,170 |
| ROCK VALLEY WATER SUPPLY | 4,059 |
| MONTICELLO WATER SUPPLY | 4,040 |
| WEST LIBERTY WATER UTILITY | 3,938 |
| CRESCO WATERWORKS | 3,913 |
| WAUKON WATER DEPARTMENT | 3,827 |
| CARTER LAKE WATER DISTRICT | 3,791 |
| EMMETSBURG MUNICIPAL WATER DEPARTMENT | 3,733 |
| WEST BURLINGTON MUNI. WATER SUPPLY | 3,728 |
| ALBIA MUNICIPAL WATER WORKS | 3,721 |
| OSAGE MUNICIPAL WATER SUPPLY | 3,637 |
| EAGLE GROVE WATER SUPPLY | 3,601 |
| NEW HAMPTON WATER SUPPLY | 3,494 |
| MILFORD MUNICIPAL UTILITIES | 3,431 |
| STORY CITY WATER DEPT | 3,357 |
| WILLIAMSBURG PUBLIC WATER SUPPLY | 3,345 |
Largest first by population served, as each employer reports it to its federal registry.
Source: U.S. Environmental Protection Agency, Safe Drinking Water Information System (SDWIS/Fed), community water systems. Data captured October 2, 2026.
Jobs at public water systems
More public employers
Other employers in Iowa
Fire departmentsTransit agenciesSchool districtsPolice departmentsSheriff's officesCampus police departmentsCommunity collegesPublic universitiesPublic librariesPublic power utilities
Public water systems in other states
Texas · 1,133California · 523Illinois · 408Alabama · 294Florida · 286Michigan · 284Tennessee · 276New York · 266Pennsylvania · 259Massachusetts · 254Ohio · 243Georgia · 242North Carolina · 237Washington · 211New Jersey · 205Missouri · 200Kentucky · 190Louisiana · 190Minnesota · 185Wisconsin · 185Indiana · 176Colorado · 167Arkansas · 157South Carolina · 143Oklahoma · 142Virginia · 142Utah · 116Oregon · 111Mississippi · 107Kansas · 88West Virginia · 82Maryland · 69Arizona · 63New Mexico · 53Idaho · 43Nebraska · 43New Hampshire · 38Hawaii · 34Montana · 32Vermont · 32Maine · 31South Dakota · 31Connecticut · 30Nevada · 28Wyoming · 28Rhode Island · 26Delaware · 20North Dakota · 18Alaska · 16District of Columbia · 3