Tap Water Quality Report
Tap water quality in RAPID CITY, South Dakota
Tap water in RAPID CITY, South Dakota receives a grade of D (64/100) from TapWaterSafety.org. It's served by RAPID CITY. The most significant water quality concerns are: Arsenic significantly above health guideline; Haloacetic acids (HAA9) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in RAPID CITY's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving RAPID CITY.
Arsenic significantly above health guideline
Moderate concernArsenic detected at 2.25 ppb, 563x above the EWG health guideline of 0.004 ppb.
Haloacetic acids (HAA9) significantly above health guideline
Moderate concernHaloacetic acids (HAA9) detected at 6.05 ppb, 101x above the EWG health guideline of 0.06 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 12.1 ppb, 81x above the EWG health guideline of 0.15 ppb.
Recommended filters for RAPID CITY
Filters matched to the specific contaminants in RAPID CITY's water supply.
Reverse Osmosis
$249-$750Arsenic is most effectively removed by reverse osmosis. Some specialized adsorptive filters also work.
Carbon block (NSF/ANSI 42 + 53)
$40-$750Activated carbon is highly effective for disinfection byproducts like TTHM and HAA5.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
All contaminants detected in RAPID CITY's tap water
Every contaminant identified, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal. Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Arsenic Heavy metal |
2.25 ppb | 0.004 | 10.0 | 10 | 10 | 0.004 | — | 563× over |
| Haloacetic acids (HAA9) Disinfection byproduct |
6.05 ppb | 0.06 | — | — | — | — | — | 101× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
12.1 ppb | 0.15 | 80.0 | 100 | — | — | — | 81× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
2.77 ppb | 0.1 | 60.0 | 60 | — | — | — | 28× over |
| Radium, combined (-226 and -228) Radiological |
0.58 pCi/L | 0.05 | 5.0 | — | — | — | — | 12× over |
| Nitrate Inorganic |
1.14 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 8.1× over |
| Chromium (hexavalent) Heavy metal |
0.132 ppb | 0.02 | — | — | — | — | — | 6.6× over |
| Chlorate Disinfection byproduct |
43.8 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Barium Heavy metal |
101.9 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Vanadium Other |
2.24 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Molybdenum Other |
0.441 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
0.295 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Strontium Radiological |
0.301 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| 1-Butanol Other |
0.116 ppb | — | — | — | — | — | — | Below guideline |
| Chlorodifluoromethane Other |
0.005 ppb | — | — | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.649 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines, California OEHHA PHGs, EWG Tap Water Database.
Treatment plant contact info
For service issues, water quality concerns, or to request a Consumer Confidence Report from RAPID CITY.