B
72

US Water Score: B

Rapid City, SD 57703

Pennington County · Population served: 14,000 · Data updated July 2026

Service-area evidence: EPA service-area records associate the listed system with this ZIP. Boundaries may still overlap or change.

Water Systems Serving This Area

🌊
BOX ELDER
Groundwater · Pop. 14,000
PWSID: SD4600046
🏔
RAPID VALLEY SANITARY DISTRICT
Surface water · Pop. 11,408
PWSID: SD4600274
🌊
CEDAR GULCH 1
Groundwater · Pop. 45
PWSID: SD4602301
🌊
DARLINGTON ESTATES
Groundwater · Pop. 25
PWSID: SD4600403

Contaminants Detected

ContaminantDetected LevelEPA MCLHealth GuidelineStatus
Lead
3.0
15 ppb 1 ppb Warning

PFAS / Forever Chemicals

2 detected 1 above comparison value

UCMR5 occurrence results are screening information, not a finding of regulatory compliance or noncompliance. PFAS rules and compliance dates are evolving.

CompoundLevelEPA MCLHealth GuidelineStatus
PFHxS5.8 ppt10 ppt10 pptBelow comparison value
PFOS5.7 ppt4 ppt4 pptAbove comparison value

Violation History (Last 5 Years)

13Total (5yr)
13Health-Based
0Major

Water Quality Summary

Understanding Your Water in Rapid City

Tap water quality in Rapid City, South Dakota (57703) receives an overall grade of B (Moderate-low record-based concern) with a score of 72 out of 100, based on analysis of EPA compliance data, contaminant testing, and violation history. This is 21 points below the South Dakota state average of 93. The area is served by 4 water systems providing water to approximately 14,000 people, using groundwater and surface water sources. Testing has found elevated levels of Lead that warrant attention. Notably, 1 PFAS compound exceeds the EPA final MCL value used for comparison — a significant concern given the persistent nature of these chemicals. Over the past 5 years, water systems here have accumulated 13 violations, including 13 health-based violations.

Your Score 72/100 B
vs State 21 pts below South Dakota avg (93)
vs National 3 pts below national avg (75)

What a Grade B Means

A score of 72/100 means Rapid City, SD performs well in the US Water Score model, with only minor system-level concerns. Residents should still review their utility's Consumer Confidence Report for official compliance information and household-specific context.

Groundwater: drawn from underground aquifers via wells
Surface water: sourced from rivers, lakes, or reservoirs

Health Information

What These Contaminants Mean for You

⚠️

Lead in Your Water

Lead is a toxic metal that can leach from aging pipes and plumbing fixtures.

Health Effects

Even low levels of lead exposure can cause developmental delays in children, kidney damage, and cardiovascular effects in adults. The EPA action level is 15 ppb, but health experts recommend no safe level of lead in drinking water.

Common Sources

Lead enters water primarily through corrosion of lead service lines, lead solder, and brass fixtures — especially in homes built before 1986.

What You Can Do

If lead is detected above 1 ppb, consider using a certified lead-removal filter (NSF/ANSI 53) for drinking and cooking water. Run cold water for 30 seconds before use if water has been sitting in pipes.

Common Questions

Frequently Asked Questions

Based on public water-system records, Rapid City, South Dakota receives an internal US Water Score grade of B (Moderate-low record-based concern) with a score of 72/100. This indicates relatively few system-level concerns in our model, but it is not an EPA safety rating and does not guarantee tap conditions inside individual homes.

ZIP code 57703 is served by 4 water systems using groundwater, surface water sources, providing water to approximately 14,000 people. Multiple source types mean your water may come from a blend of surface and underground sources.

Lead was reported at 3.0 ppb in public-system records for Rapid City, South Dakota. This is below the currently applicable EPA action level of 15 ppb, but may be above more protective health guidance; EPA's future LCRI action level is 10 ppb. Household plumbing can materially change tap-level exposure, so consider certified filtration and individual tap testing, especially where children are present.

Yes — 2 PFAS compounds were detected in records associated with water serving Rapid City, South Dakota, and 1 result exceeded the numerical EPA MCL value used for comparison. UCMR5 occurrence results alone are not a regulatory compliance determination. PFAS rules and compliance timelines are evolving; verify current information with the utility and EPA.

Water systems serving Rapid City, South Dakota have received 13 violations in the last 5 years, including 13 health-based violations. Violations can range from paperwork issues (monitoring & reporting) to serious health-based violations where contaminant levels exceeded safe limits. Review the violation details above for specifics.

Based on detected contaminants (lead, PFAS), residents in Rapid City, South Dakota should consider: Reverse osmosis (RO) system — most effective for PFAS, lead, and other contaminants. Always look for filters with NSF/ANSI certification for the specific contaminants you want to remove.

Explore Nearby

Water Quality in Nearby ZIP Codes