Rapid City, SD Water Quality (ZIP 57702)

Quick Answers

Is ZIP 57702 tap water safe to drink? PFAS compounds have been detected in 57702's water at an average of 4.85 ppt across 1 compound. A certified pitcher filter or reverse osmosis system is recommended, especially for sensitive populations.

What filter should I use in 57702? Match the filter to the data: reverse osmosis handles PFAS, lead, and arsenic together; NSF-53 pitchers cover the taps you drink from. A basic Brita pitcher will not remove PFAS.

ZIP 57702 Water Quality Summary

EPA testing has detected PFAS "forever chemicals" in the water system serving ZIP 57702 (Rapid City, SD). Monitoring found a peak of 5.6 ppt across 1 system, averaging 4.85 ppt over 1 detected compound. These levels come from individual EPA UCMR 5 water samples (2023-2025). The EPA's 4 ppt limit for PFOA and PFOS is enforced on a running annual average, so a sample above it shows real exposure but is not by itself a violation.

Contamination Level: LOW – Low contamination – PFAS detected but at lower levels; monitoring continues.

Top Detected Compounds in ZIP 57702

• PFHXS: 5.6 ppt

Lead in ZIP 57702 Water

EPA Lead and Copper Rule testing recorded 6 lead samples for the system serving 57702, with a 90th-percentile high of 0.006 mg/L (within the EPA 0.015 mg/L action level). There is no safe level of lead for children; homes built before 1986 should use a certified NSF/ANSI 53 lead filter.

EPA Violations Affecting ZIP 57702

The water system serving 57702 has 1 health-based EPA Safe Drinking Water Act violation on record, including Stage 1 Disinfectants and Disinfection Byproducts Rule. A health-based violation means a contaminant exceeded its federal limit or required treatment was not applied.

About the Data

These figures come from EPA UCMR5 (2023-2025) plus Lead and Copper Rule and SDWIS records for the public water system serving ZIP 57702. UCMR5 is the most comprehensive national drinking water survey in US history.

Beyond water: other exposures in Rapid City, SD

Drinking water is one exposure route. These are the other federal datasets that cover ZIP 57702 and Pennington County, SD.

Radon risk in Pennington County, SD

The EPA places Pennington County, SD in Zone 2 - a moderate-risk category, with a predicted average indoor radon level between 2 and 4 pCi/L. Zone maps predict the radon potential of an area from geology and existing indoor readings - they do not describe any individual home. Radon is the leading cause of lung cancer among people who have never smoked, and the only way to know your own level is a test kit.

Lead paint risk in Pennington County, SD

Census figures show 49% of homes in Pennington County, SD were built before 1980, and 9% before 1950. Lead-based paint was banned for residential use in 1978, so older housing stock is the strongest available proxy for lead-paint exposure. This is a statistic about the county's housing, not a test of any particular property - if your home predates 1980, a lead swab test is the way to check.

Air quality in Pennington County, SD

Modelled annual fine-particle pollution (PM2.5) for Pennington County, SD averages 5.8 µg/m³, within the EPA's annual PM2.5 standard of 9 µg/m³. PM2.5 is the pollution fraction small enough to reach deep into the lungs. These are CDC modelled estimates for the county as a whole, not a reading taken at this ZIP code.