South Dakota Water Systems Serving the Most Disadvantaged Populations — 2026
South Dakota 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 34 South Dakota 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 | Huron | South Dakota | 12,385 | 72.2 | 35% | 39% | — |
| 2 | Brown-Day-Marshall Rws | South Dakota | 3,817 | 71.4 | 40% | 36% | — |
| 3 | Tripp County Water User District | South Dakota | 4,937 | 61.4 | 21% | 39% | — |
| 4 | Randall Community Water District | South Dakota | 4,286 | 59.2 | 23% | 36% | — |
| 5 | Vermillion | South Dakota | 7,984 | 57.2 | 15% | 43% | — |
| 6 | Rapid City | South Dakota | 66,163 | 48 | 22% | 29% | — |
| 7 | Brookings Municipal Utilities | South Dakota | 21,230 | 45.3 | 13% | 34% | — |
| 8 | Aberdeen | South Dakota | 17,984 | 41 | 17% | 28% | 1 |
| 9 | Big Sioux Community Water System | South Dakota | 3,557 | 41 | 20% | 26% | — |
| 10 | Mid-Dakota Rural Water | South Dakota | 14,661 | 39.9 | 18% | 26% | — |
| 11 | Mitchell | South Dakota | 10,986 | 39.6 | 11% | 32% | — |
| 12 | Davison Rural Water System Inc. | South Dakota | 7,919 | 36.8 | 10% | 31% | — |
| 13 | Rapid Valley Sanitary District | South Dakota | 11,176 | 35.8 | 23% | 19% | — |
| 14 | Brookings-Deuel Rural Water System | South Dakota | 4,571 | 35.5 | 11% | 30% | — |
| 15 | Sturgis | South Dakota | 6,332 | 34.8 | 9% | 30% | — |
| 16 | Clay Rural Water System | South Dakota | 3,913 | 34.8 | 11% | 29% | — |
| 17 | Web Water Development Association | South Dakota | 20,409 | 34.8 | 13% | 27% | — |
| 18 | Pierre | South Dakota | 9,980 | 34.6 | 19% | 21% | — |
| 19 | Spearfish | South Dakota | 4,816 | 32 | 11% | 27% | — |
| 20 | Minnehaha Community Water Corporation | South Dakota | 25,510 | 31.6 | 17% | 21% | — |
| 21 | Southern Black Hills Water | South Dakota | 7,456 | 31.6 | 13% | 25% | — |
| 22 | Clark Rural Water System | South Dakota | 4,320 | 30.3 | 7% | 29% | — |
| 23 | Watertown Municipal Utilities | South Dakota | 18,319 | 29.8 | 9% | 27% | — |
| 24 | Belle Fourche | South Dakota | 3,480 | 29.6 | 11% | 25% | — |
| 25 | Yankton | South Dakota | 6,732 | 29.4 | 14% | 22% | — |
| 26 | Madison | South Dakota | 5,564 | 28.9 | 8% | 28% | — |
| 27 | By Water District | South Dakota | 14,436 | 28.3 | 11% | 24% | — |
| 28 | Sioux Rural Water System | South Dakota | 7,503 | 27.8 | 8% | 27% | — |
| 29 | Tm Rural Water District | South Dakota | 3,939 | 24.5 | 8% | 25% | — |
| 30 | Lincoln County Rural Water System | South Dakota | 29,830 | 22.5 | 14% | 17% | — |
| 31 | Sioux Falls | South Dakota | 173,512 | 21.1 | 21% | 25% | — |
| 32 | Kingbrook I Rural Water System | South Dakota | 7,552 | 19.4 | 8% | 21% | — |
| 33 | South Lincoln Rural Water System | South Dakota | 6,798 | 16.6 | 8% | 19% | — |
| 34 | Brandon | South Dakota | 7,948 | 7.4 | 9% | 9% | — |
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.