PFAS above a 2024 limit
MCL1of 15 cities
Cities whose system reported a PFAS above its federal limit.
PFOS in South Dakota →State water report
South Dakota Water Quality: 15 Cities Ranked by the Records
Water quality across 15 cities in South Dakota, drawn from EPA drinking-water records. Each city page shows the measured contaminants and a reproducible Purity Score.
Finding by finding
What South Dakota's records show
Counts of cities whose serving system reported each result. There is no statewide score: PurityMap does not average local records into a statewide safety verdict. 1 city has a past health-based violation on record.
Lead detected
Action level14of 15 cities
90th-percentile lead above zero.
Lead across South Dakota →Lead above action level
Action level0of 15 cities
No city on record above 15 µg/L.
How lead is measured →City rankings
South Dakota cities ranked by the records
Highest first. A summary of each serving system’s record, not a safety verdict.
- 1MitchellMITCHELL · SD4600214Report →
- 2PierrePIERRE · SD4600242Report →
- 3VermillionVERMILLION · SD4600342Report →
- 4BrandonBRANDON · SD4600048Report →
- 5HarrisburgHARRISBURG · SD4600148Report →
- 6WatertownWATERTOWN MUNICIPAL UTILITIES · SD4600356Report →
- 7YanktonYANKTON · SD4600423Report →
- 8By DistrictBY WATER DISTRICT · SD4600865Report →
- 9Sioux FallsSIOUX FALLS · SD4600294Report →
- 10SpearfishSPEARFISH · SD4600311Report →
Showing the top 10 of 15 scored cities.
Highest detected PFOS result first. The tick marks the 4.0 ng/L federal MCL.
- 1Rapid Valley Sanitary DistrictRAPID VALLEY SANITARY DISTRICT · SD46002745.7 ng/LReport →
Showing the top 1 of 1 cities with a pfas result.
Highest 90th-percentile result first. The tick marks the 15 µg/L action level.
- 1BrookingsBROOKINGS MUNICIPAL UTILITIES · SD46000718 µg/LReport →
- 2Rapid CityRAPID CITY · SD46004066 µg/LReport →
- 3Sioux FallsSIOUX FALLS · SD46002943 µg/LReport →
- 4AberdeenABERDEEN · SD46000203 µg/LReport →
- 5SpearfishSPEARFISH · SD46003113 µg/LReport →
- 6Rapid Valley Sanitary DistrictRAPID VALLEY SANITARY DISTRICT · SD46002743 µg/LReport →
- 7WatertownWATERTOWN MUNICIPAL UTILITIES · SD46003562 µg/LReport →
- 8Box ElderBOX ELDER · SD46000462 µg/LReport →
- 9MitchellMITCHELL · SD46002141 µg/LReport →
- 10PierrePIERRE · SD46002421 µg/LReport →
Showing the top 10 of 14 cities with a lead result.
See all 15 in the table
15 cities, highest Purity Score first
- MITCHELL · PWSID SD4600214 · Purity Score 99/100 (Excellent) · Confidence: moderate · Assessed at the water-system levelNo PFAS detected; lead 1 µg/LDetected
- PIERRE · PWSID SD4600242 · Purity Score 99/100 (Excellent) · Confidence: moderate · Assessed at the water-system levelNo PFAS detected; lead 1 µg/LDetected
- VERMILLION · PWSID SD4600342 · Purity Score 99/100 (Excellent) · Confidence: moderate · Assessed at the water-system levelNo PFAS detected; lead 1 µg/LDetected
- BRANDON · PWSID SD4600048 · Purity Score 99/100 (Excellent) · Confidence: moderate · Assessed at the water-system levelNo PFAS detected; lead 1 µg/LDetected
- HARRISBURG · PWSID SD4600148 · Purity Score 99/100 (Excellent) · Confidence: moderate · Assessed at the water-system levelPFBA 5.5 ng/L detected, no federal or state limit; lead 1 µg/LDetected
- WATERTOWN MUNICIPAL UTILITIES · PWSID SD4600356 · Purity Score 98/100 (Excellent) · Confidence: moderate · Assessed at the water-system levelNo PFAS detected; lead 2 µg/LDetected
- YANKTON · PWSID SD4600423 · Purity Score 98/100 (Excellent) · Confidence: moderate · Assessed at the water-system levelNo PFAS detectedNot detected
- BY WATER DISTRICT · PWSID SD4600865 · Purity Score 98/100 (Excellent) · Confidence: moderate · Assessed at the water-system levelNo PFAS detected; lead 1 µg/LDetected
- SIOUX FALLS · PWSID SD4600294 · Purity Score 97/100 (Excellent) · Confidence: moderate · Assessed at the water-system levelNo PFAS detected; lead 3 µg/LDetected
- SPEARFISH · PWSID SD4600311 · Purity Score 97/100 (Excellent) · Confidence: moderate · Assessed at the water-system levelNo PFAS detected; lead 3 µg/LDetected
- BROOKINGS MUNICIPAL UTILITIES · PWSID SD4600071 · Purity Score 90/100 (Excellent) · Confidence: moderate · Assessed at the water-system levelNo PFAS detected; lead 8 µg/LDetected
- BOX ELDER · PWSID SD4600046 · Purity Score 88/100 (Good) · Confidence: moderate · Assessed at the water-system levelPast gross alpha particles and combined radium-226/228 violation on recordDetected
- RAPID CITY · PWSID SD4600406 · Purity Score 84/100 (Good) · Confidence: moderate · Assessed at the water-system levelPFAS detected below EPA limits; lead 6 µg/LDetected
- 14AberdeenABERDEEN · PWSID SD4600020 · Purity Score 84/100 (Good) · Confidence: moderate · Assessed at the water-system levelPFBA 8.1 ng/L detected, no federal or state limit; lead 3 µg/LDetected
- RAPID VALLEY SANITARY DISTRICT · PWSID SD4600274 · Purity Score 66/100 (Fair) · Confidence: moderate · Assessed at the water-system levelPFOS 5.7 ng/L, 1.4× the EPA limitAbove reference
Showing 12 of 15.
Ranked by the Purity Score of each city's main water system, highest first. Scores belong to water systems; there is no state score. The score is computed only from contaminants measured in the published EPA record, so this ranks the record, not which city's water is safest. How the score works. See how South Dakota compares with other states.
By contaminant
PFAS and lead in South Dakota
PFAS
MCLHighest detected PFOS result, by city.
- Rapid Valley Sanitary District5.7 ng/L
| 4.0 ng/L federal MCL · 1 city above it
Lead
Action level90th-percentile result, by city.
- Brookings8 µg/L
- Rapid City6 µg/L
- Sioux Falls3 µg/L
- Aberdeen3 µg/L
- Spearfish3 µg/L
| 15 µg/L action level · none above
Counties
12 counties with city reportsSouth Dakota counties
- Minnehaha County2 cities
- Brookings County1 city
- Brown County1 city
- Clay County1 city
- Codington County1 city
- Davison County1 city
- Hughes County1 city
- Lawrence County1 city
- Lincoln County1 city
- Meade County1 city
Show all 12 counties
- Pennington County1 city
- Yankton County1 city
Suppliers
Largest water systems
- SIOUX FALLSSioux Falls · SD4600294 · 216,462 served
- RAPID CITYRapid City · SD4600406 · 72,009 served
- ABERDEENAberdeen · SD4600020 · 27,989 served
- BROOKINGS MUNICIPAL UTILITIESBrookings · SD4600071 · 23,377 served
- WATERTOWN MUNICIPAL UTILITIESWatertown · SD4600356 · 23,230 served
- MITCHELLMitchell · SD4600214 · 15,651 served
Full indexAll 15 South Dakota city reports, A–Z
Next step
State patterns can’t tell you what reaches your tap.
Learn
Learn your supplier
Resolve your address to the one public water system that serves it.
Find my water →Test
Test your own tap
Plumbing inside a building can add lead and change what reaches your glass.
How to test →Solve
Treat by concern
Only after a city report names a finding, match a treatment certified for it.
Treatment options →Questions
South Dakota water, frequently asked
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How does South Dakota tap water compare across cities?
PurityMap ranks 15 cities in South Dakota by the Purity Score of each city's main water system, computed only from contaminants measured in the published EPA record. Scores belong to water systems, not to cities. The highest published score is Mitchell's main water system: MITCHELL · PWSID SD4600214 · Purity Score 99 (Excellent) · Confidence: moderate · Assessed at the water-system level. The ranking compares the records, not which city's water is safest, and your own tap can differ with household plumbing.
How many South Dakota cities have PFAS above the federal limit?
1 city of 15 had at least one regulated PFAS (PFOA, PFOS or PFHxS) measured above the 2024 federal limit in EPA's UCMR 5 testing, including Rapid Valley Sanitary District (PFOS 5.7 ng/L). PFAS were detected at any level in 4.
Is there lead in South Dakota tap water?
Utilities report lead as a 90th-percentile result from home taps. 14 of 15 South Dakota cities reported a value above zero, and none was above the 15 µg/L federal action level. Lead usually comes from a building's own pipes and fixtures, so only a test at your tap tells you what you drink.
Have South Dakota water systems had drinking-water violations?
1 city in South Dakota has a health-based violation in the federal SDWIS record within about the last ten years. Each city report lists the contaminant, year and whether it was resolved.
Limits, sources and corrections
A statewide page cannot tell you what reaches a specific address. Water quality varies by supplier, sampling period and household plumbing; open a city report for the evidence behind a local result.
Sources: EPA UCMR 5 (PFAS, 2024), SDWIS Lead and Copper Rule 90th-percentile results and health-based violations, and utility Consumer Confidence Reports where on file. Every city report links its dated source records.
Updated 2026-09-16. How PurityMap analyzes water data · Report an error