Is Rapid City Tap Water Safe? Quality Report

Water source: Surface water
Ownership: Local government
Counties served: Pennington

Compliance record

Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.

health-based violations

violations on file

still open

Violation	Type	Status	Period
MR	Monitoring	Resolved	2002-10-01 → 2002-12-31
MR	Monitoring	Resolved	2002-10-01 → 2002-12-31
MR	Monitoring	Resolved	2002-10-01 → 2002-12-31
MR	Monitoring	Resolved	2002-10-01 → 2002-12-31
MR	Monitoring	Resolved	2002-10-01 → 2002-12-31
MR	Monitoring	Resolved	2002-10-01 → 2002-12-31
MR	Monitoring	Resolved	2002-10-01 → 2002-12-31
MR	Monitoring	Resolved	2002-10-01 → 2002-12-31
MR	Monitoring	Resolved	2002-10-01 → 2002-12-31
MR	Monitoring	Archived	1999-04-01 → 1999-04-30

PFAS detected

PFAS are industrial “forever chemicals”. These are the EPA's latest nationwide test results (2023–2025).

Contaminant	Max	Detection rate	Period
PFHXS	0.0056 µg/L	2/20	2025

Other contaminants detected

Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the 95th percentile of this system's samples — over 100% is worth reading, but is not by itself a violation. Where a single sample came in higher than that percentile, it is noted under the bar. Formal violations are listed separately.

Contaminant	Level vs EPA limit	Detection rate	Source	Period
TTHM	28.85 µg/L 36% of the EPA limit 80 µg/L worst single sample: 45 µg/L	124/128	SYR4	2012–2019
Copper	311.7 µg/L 24% of the EPA limit 1300 µg/L worst single sample: 343 µg/L	90/90	SYR4	2012–2018
Lead	4 µg/L 27% of the EPA limit 15 µg/L worst single sample: 7 µg/L	90/90	SYR4	2012–2018
Total Haloacetic Acids (HAA5)	18.45 µg/L 31% of the EPA limit 60 µg/L worst single sample: 24 µg/L	52/127	SYR4	2012–2019
Nitrate	1443.5 µg/L 14% of the EPA limit 10000 µg/L worst single sample: 1710 µg/L	34/56	SYR4	2013–2019
Lead	0.0060 mg/L 40% of the EPA limit 0.0150 mg/L	15/15	LCR	2024
Barium	134.5 µg/L 6.7% of the EPA limit 2000 µg/L worst single sample: 140 µg/L	12/12	SYR4	2012–2019
Arsenic	6 µg/L 60% of the EPA limit 10 µg/L	4/13	SYR4	2012–2019
Gross Alpha, Excl. Radon And U	6.594 pCi/L 44% of the EPA limit 15 pCi/L worst single sample: 7.32 pCi/L	4/13	SYR4	2012–2018
Gross Beta Particle Activity	3.5 pCi/L No EPA limit set	1/13	SYR4	2012–2018
Nitrite	200 µg/L 20% of the EPA limit 1000 µg/L	1/12	SYR4	2012–2018

38 contaminants tested, none detected

11Cl-PF3OUdS4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalBeryllium, TotalCadmiumChromiumCombined Radium (-226 And -228)Combined UraniumHfpo-DaMercuryNetfosaaNfdhaNmefosaaPfbaPFBSPfdaPfdoaPfeesaPfhpaPfhpsPfhxaPfmbaPfmpaPFNAPFOAPFOSPfpeaPfpesPftaPftrdaPfunaSeleniumThallium, TotalLithium

Utility contact

Contact: ERIC BOYDA
Phone: 6053944162
Email: [email protected]

Frequently asked questions about Rapid City

Is Rapid City tap water safe to drink?

EPA monitoring detected 12 contaminants in Rapid City's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.

What contaminants were detected in Rapid City's water?

EPA monitoring detected TTHM, Copper, Lead, Total Haloacetic Acids (HAA5), Nitrate, and others. The full list with the level and data source for each is above.

How many people does Rapid City serve?

Rapid City reports serving 72,009 people in South Dakota, per its EPA record.

Has Rapid City had any water quality violations?

The EPA has 13 violations on file for Rapid City, of which 0 are health-based (a contaminant limit or required treatment was breached) and 0 remain open. The rest are monitoring or reporting failures.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.