Iowa Water Systems Serving the Most Disadvantaged Populations — 2026
Iowa community water utilities serving populations with the highest combined percent of non-white residents and households below 200% of the Federal Poverty Level (Census ACS 2019-2023, aggregated via EPA CWS Service Area Boundaries v3).
ranked
with demographic data
vintage
boundaries (March 2026)
These 50 Iowa water utilities serve populations with the highest combined percent of non-white residents and households below 200% of the Federal Poverty Level. Within-size-class percentile rankings neutralize the confound of system size; no geographic cap is applied at the state level because all utilities are within a single state.
| Rank | Water System | State | Pop served | Equity score | % PoC served | % Below 200% FPL | Unresolved violations |
|---|---|---|---|---|---|---|---|
| 1 | Storm Lake Water Treatment Plant | Iowa | 6,842 | 80.4 | 58% | 37% | — |
| 2 | Denison Water Supply | Iowa | 6,944 | 80.2 | 52% | 38% | — |
| 3 | Waterloo Water Works | Iowa | 58,142 | 68.6 | 31% | 38% | — |
| 4 | Iowa City Water Department | Iowa | 67,537 | 68 | 27% | 40% | — |
| 5 | Marshalltown Water Works | Iowa | 25,895 | 66.6 | 40% | 33% | — |
| 6 | Sioux City Water Supply | Iowa | 68,144 | 64.6 | 35% | 33% | — |
| 7 | Osceola Water Works | Iowa | 5,037 | 62.7 | 26% | 37% | — |
| 8 | Isu | Iowa | 10,746 | 62 | 20% | 41% | — |
| 9 | Fairfield Water Supply | Iowa | 8,714 | 61.8 | 20% | 41% | — |
| 10 | Ottumwa Water Works | Iowa | 23,740 | 61.6 | 26% | 36% | — |
| 11 | Hampton Muni Water Works | Iowa | 3,612 | 59.5 | 24% | 36% | — |
| 12 | Perry Municipal Water Works | Iowa | 7,633 | 59.4 | 31% | 31% | — |
| 13 | Evansdale Water Works | Iowa | 5,090 | 58.8 | 20% | 39% | — |
| 14 | Ames Water Treatment Plant | Iowa | 56,104 | 58.8 | 22% | 37% | — |
| 15 | Coralville Muni Water System | Iowa | 16,382 | 55 | 36% | 26% | — |
| 16 | Clarinda Water Plant | Iowa | 4,625 | 54.2 | 13% | 42% | — |
| 17 | Muscatine Power & Water | Iowa | 17,485 | 54.1 | 24% | 32% | — |
| 18 | Sheldon Water Department | Iowa | 4,807 | 50.6 | 19% | 33% | — |
| 19 | Washington Water Department | Iowa | 6,911 | 50.4 | 16% | 35% | — |
| 20 | Centerville Municipal Waterworks | Iowa | 5,086 | 50.3 | 7% | 48% | — |
| 21 | Keokuk Municipal Water Works | Iowa | 5,437 | 49.9 | 9% | 42% | — |
| 22 | Iowa-American Wtr Company-Clinton District | Iowa | 17,226 | 49.1 | 14% | 36% | — |
| 23 | Cherokee Rws - Cherokee Subsystem | Iowa | 4,136 | 48.2 | 11% | 38% | — |
| 24 | Cherokee Water Supply - Plant 1 | Iowa | 4,527 | 48.2 | 11% | 38% | — |
| 25 | Burlington Municipal Waterworks | Iowa | 19,065 | 47.3 | 17% | 32% | — |
| 26 | Fort Dodge Water Supply | Iowa | 22,881 | 46.8 | 18% | 31% | — |
| 27 | Oelwein Municipal Water Works | Iowa | 5,405 | 46.4 | 10% | 39% | — |
| 28 | Webster City Water Supply | Iowa | 7,123 | 46 | 21% | 29% | — |
| 29 | Mount Pleasant Municipal Utilities | Iowa | 8,681 | 44.6 | 17% | 30% | — |
| 30 | Council Bluffs Water Works | Iowa | 53,006 | 44 | 16% | 31% | — |
| 31 | Newton Water Supply | Iowa | 15,759 | 43.4 | 12% | 34% | — |
| 32 | Charles City Water Supply | Iowa | 6,766 | 43.2 | 13% | 33% | — |
| 33 | Des Moines Water Works | Iowa | 237,110 | 42 | 33% | 32% | — |
| 34 | Estherville Water Treatment Plant | Iowa | 5,651 | 41.9 | 17% | 28% | — |
| 35 | Shenandoah Water Department | Iowa | 4,832 | 41 | 6% | 38% | — |
| 36 | Mason City Water Department | Iowa | 25,391 | 39.9 | 13% | 30% | — |
| 37 | Oskaloosa Municipal Water Dept | Iowa | 11,425 | 39.7 | 9% | 35% | — |
| 38 | Waukon Water Department | Iowa | 3,402 | 37.1 | 7% | 34% | — |
| 39 | Chariton Municipal Water Works | Iowa | 3,654 | 37.1 | 5% | 36% | — |
| 40 | Atlantic Municipal Utilities | Iowa | 6,247 | 36.8 | 4% | 36% | — |
| 41 | Creston Water Supply | Iowa | 7,284 | 36.6 | 6% | 35% | — |
| 42 | Rathbun Regional Water Assn (Rathbun) | Iowa | 19,674 | 35.8 | 6% | 34% | — |
| 43 | Red Oak Water Supply | Iowa | 5,016 | 35.2 | 9% | 31% | — |
| 44 | Nevada Water Supply | Iowa | 6,085 | 35.1 | 17% | 24% | — |
| 45 | Sioux Center Municipal Water Department | Iowa | 7,300 | 35 | 18% | 23% | — |
| 46 | Dubuque Water Works | Iowa | 55,668 | 34.8 | 13% | 27% | — |
| 47 | Forest City Water Supply | Iowa | 3,391 | 34.2 | 12% | 27% | — |
| 48 | Rathbun Reg Wtr Assn (Burlington) | Iowa | 10,936 | 33.8 | 11% | 28% | — |
| 49 | Urbandale Water Utility | Iowa | 32,108 | 33.2 | 23% | 18% | — |
| 50 | West Des Moines Water Works | Iowa | 51,195 | 32.8 | 22% | 18% | — |
How to read this ranking
Each row links to a full utility profile with violation history, lead testing results, and service-area ZIPs. The demographic context columns are from independent data sources (ACS, not EJScreen) and are provided for readers who want to examine equity patterns alongside the operational data.
See the full methodology for calculation details, data vintages, and known limitations.
Frequently asked questions
What does the "equity score" mean?
A 0-100 composite that combines two within-size-class percentile ranks: (1) percent of population served that is non-white (Census ACS B03002), and (2) percent below 200 percent of the Federal Poverty Level (Census ACS C17002). Within-size-class comparison (small, medium, large) is used because small rural systems and large urban systems have structurally different demographic profiles; mixing them in a single ranking produces a methodologically weak list dominated by size rather than disparity.
Why is the list capped at 5 systems per state?
Without a cap, the list concentrates in states with large numbers of historically disadvantaged small-to-medium systems (Texas, California). A geographic diversity cap produces a more nationally-representative snapshot. Per-state rankings, if available, show the full within-state comparison without a cap.
Does this claim discrimination?
No. It reports a demographic fact: these water utilities serve populations that are more non-white and lower-income than the national median, after controlling for system size. Causation — why that pattern exists — is a separate research question requiring different data and methods.
ZipCheckup is an independent public-data tool. We are a referral service and do not provide water testing, remediation, or utility services. Rankings reflect publicly-available federal data and are provided for informational purposes. For issues with your specific water system, contact your local water utility or state drinking water program.