All 52 systems had enough required samples to calculate a yearly average. 0 had at least one yearly average at or above a study benchmark; 52 did not.
EPA-based study benchmark: the unrounded cutoff this research uses to reproduce EPA’s January 2026 technical-assistance classification around the April 2024 federal levels. It is not a current standard or compliance finding and cannot determine household exposure or health risk.
Find your water system
ZIP codes are used only to route visitors to public water systems that reported serving them. Confirm the actual provider using a water bill or utility record.
System counts in South Dakota
Each count shows how many included water systems had a yearly average at or above the named study benchmark.
| Study benchmark | Systems at or above benchmark | Water systems included | Percent |
|---|---|---|---|
| PFOA: 4.05 ppt study benchmark (reproduces EPA classification around 4 ppt) | 0 | 52 | 0.0% |
| PFOS: 4.05 ppt study benchmark (reproduces EPA classification around 4 ppt) | 0 | 52 | 0.0% |
| PFHxS: 15 ppt study benchmark (reproduces EPA classification around 10 ppt) | 0 | 52 | 0.0% |
| PFNA: 15 ppt study benchmark (reproduces EPA classification around 10 ppt) | 0 | 52 | 0.0% |
| HFPO-DA: 15 ppt study benchmark (reproduces EPA classification around 10 ppt) | 0 | 52 | 0.0% |
| Hazard Index: 1.5 study benchmark with at least two detected components (reproduces EPA classification around 1) | 0 | 52 | 0.0% |
Community water systems with complete monitoring
“Complete monitoring” means at least one sampling location had all required samples needed for a yearly average. Each PWSID appears once, preventing double counting across ZIP associations.
| Public water system | PWSID | Population served | Primary source | Sampling locations | Study benchmark result |
|---|---|---|---|---|---|
| ABERDEEN | SD4600020 | 27,989 | Surface water | 1 | Below all study benchmarks |
| BELLE FOURCHE | SD4600037 | 5,617 | Ground water | 3 | Below all study benchmarks |
| BIG SIOUX COMMUNITY WATER SYSTEM | SD4600429 | 5,800 | Ground water | 3 | Below all study benchmarks |
| BLACK HAWK WATER USER DISTRICT | SD4600043 | 4,500 | Ground water | 3 | Below all study benchmarks |
| BON HOMME-YANKTON RWS | SD4600865 | 13,320 | Surface water | 1 | Below all study benchmarks |
| BOX ELDER | SD4600046 | 14,000 | Ground water | 3 | Below all study benchmarks |
| BRANDON | SD4600048 | 11,048 | Ground water | 1 | Below all study benchmarks |
| BROOKINGS MUNICIPAL UTILITIES | SD4600071 | 23,377 | Ground water | 2 | Below all study benchmarks |
| BROOKINGS-DEUEL RURAL WATER SYSTEM | SD4600430 | 6,200 | Ground water | 2 | Below all study benchmarks |
| BROWN-DAY-MARSHALL RWS | SD4600882 | 5,673 | Ground water | 1 | Below all study benchmarks |
| CLAY RURAL WATER SYSTEM | SD4600626 | 4,780 | Ground water | 1 | Below all study benchmarks |
| DELL RAPIDS | SD4600105 | 3,633 | Ground water purchased | 1 | Below all study benchmarks |
| EAGLE BUTTE | SD4600010 | 4,000 | Surface water purchased | 1 | Below all study benchmarks |
| ELLSWORTH AFB | SD4680004 | 9,100 | Surface water purchased | 1 | Below all study benchmarks |
| GRANT-ROBERTS RURAL WATER SYSTEM | SD4600864 | 5,050 | Ground water | 1 | Below all study benchmarks |
| HARRISBURG, SD | SD4600148 | 10,297 | Ground water purchased | 2 | Below all study benchmarks |
| HURON | SD4600169 | 14,263 | Surface water purchased | 1 | Below all study benchmarks |
| KINGBROOK I RURAL WATER SYSTEM | SD4600431 | 6,455 | Ground water purchased | 1 | Below all study benchmarks |
| KYLE WATER SYSTEM | 084690474 | 6,526 | Surface water purchased | 2 | Below all study benchmarks |
| LINCOLN COUNTY RURAL WATER SYSTEM | SD4600304 | 5,965 | Ground water purchased | 2 | Below all study benchmarks |
| MADISON | SD4600199 | 6,191 | Ground water | 2 | Below all study benchmarks |
| MID-DAKOTA RURAL WATER | SD4602175 | 11,833 | Surface water | 1 | Below all study benchmarks |
| MINNEHAHA COMMUNITY WATER CORP | SD4600432 | 13,435 | Ground water | 2 | Below all study benchmarks |
| MISSION WATER SYSTEM | 084690532 | 1,500 | Surface water purchased | 1 | Below all study benchmarks |
| MITCHELL | SD4600214 | 15,651 | Surface water purchased | 1 | Below all study benchmarks |
| MOBRIDGE | SD4600215 | 3,261 | Surface water | 1 | Below all study benchmarks |
| OGLALA RWS PIPELINE | 084690480 | 3,562 | Ground water | 1 | Below all study benchmarks |
| PHILIP | SD4600238 | 759 | Surface water purchased | 1 | Below all study benchmarks |
| PIERRE | SD4600242 | 14,091 | Surface water | 1 | Below all study benchmarks |
| PINE RIDGE WATER SYSTEM | 084690475 | 7,482 | Ground water | 3 | Below all study benchmarks |
| RANDALL COMMUNITY WATER DISTRICT | SD4600433 | 6,248 | Surface water | 2 | Below all study benchmarks |
| RAPID CITY | SD4600406 | 72,009 | Surface water | 8 | Below all study benchmarks |
| RAPID VALLEY SANITARY DISTRICT | SD4600274 | 11,408 | Surface water | 1 | Below all study benchmarks |
| RENDEZVOUS RANCH | SD4602210 | 195 | Ground water | 1 | Below all study benchmarks |
| SICANGU MNI WICONI RURAL WATER SYSTEM | 084690516 | 5,610 | Surface water purchased | 1 | Below all study benchmarks |
| SIOUX FALLS | SD4600294 | 216,462 | Surface water | 2 | Below all study benchmarks |
| SIOUX RURAL WATER SYSTEM | SD4600866 | 4,280 | Ground water | 2 | Below all study benchmarks |
| SOUTH LINCOLN RURAL WATER SYSTEM | SD4600870 | 5,250 | Ground water | 2 | Below all study benchmarks |
| SPEARFISH | SD4600311 | 13,803 | Ground water | 7 | Below all study benchmarks |
| ST. FRANCIS | 084690020 | 2,450 | Ground water | 1 | Below all study benchmarks |
| STANDING ROCK RURAL WATER SYSTEM | 084690510 | 6,839 | Surface water | 1 | Below all study benchmarks |
| STURGIS | SD4600321 | 7,020 | Ground water | 1 | Below all study benchmarks |
| SUN VALLEY DEVELOPMENT | SD4602270 | 650 | Ground water | 1 | Below all study benchmarks |
| TEA | SD4600409 | 7,381 | Ground water purchased | 1 | Below all study benchmarks |
| TM RURAL WATER DISTRICT | SD4600999 | 4,250 | Surface water purchased | 3 | Below all study benchmarks |
| TMT, INC. | SD4602154 | 250 | Surface water purchased | 1 | Below all study benchmarks |
| VERMILLION | SD4600342 | 11,695 | Ground water | 1 | Below all study benchmarks |
| WALL | SD4600417 | 699 | Ground water | 4 | Below all study benchmarks |
| WATERTOWN MUNICIPAL UTILITIES | SD4600356 | 23,230 | Ground water | 1 | Below all study benchmarks |
| WEB WATER DEVELOPMENT ASSOCIATION | SD4601089 | 20,750 | Surface water | 1 | Below all study benchmarks |
| WR/LJ - MNI WICONI | SD4602223 | 4,720 | Surface water purchased | 1 | Below all study benchmarks |
| YANKTON | SD4600423 | 15,411 | Ground water | 1 | Below all study benchmarks |
What is included
Each active community water system with enough required samples for a yearly average is counted once, even if it is linked with several ZIP codes. This does not mean every home was tested. Private wells are excluded, and UCMR 5 did not comprehensively monitor every small system. This page does not apply South Dakota's state-specific standards or determine compliance. Use the official state or territory drinking-water program for current regulatory information.