Rapid City serves 72,009 people from surface water. 31 results are on record. No measured result is above a legal limit.
No measured result is above a legal limit.
23,451service lines inventoried
From the utility's inventory reported to EPA (2026Q2). Look up your address with the utility.
0health-based violations in the last 10 years
From EPA SDWIS. A clean violation history means no enforcement action was recorded; it does not cover contaminants without a limit.
No result is not a pass. Your utility's annual water quality report may list them, and a certified lab test covers your own tap.
A federal limit (an MCL or action level) is an enforceable legal cap; a health goal is often stricter. Meeting the limit is a compliance fact, not a health clearance, and PurityMap publishes no overall compliance verdict.
Plumbing inside a home can add lead that the system record can't show. A tap test tells you what reaches your glass.
lead 6 µg/L, below the 15 µg/L action level
PFHxS 5.6 ng/L, below the 10 ng/L limit
Understand water treatment technologies →
Understand:PFAS in Rapid CityLead in Rapid City
Screening tells you if something is worth a closer look; a lab result is the number you can act on.
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Screening: quick check, not lab-grade
Safe Home (EnviroTestKits)
Lead, read as one of three ranges: 0–4, 5–15 or 15+ ppb
What it can't tell you: It shows a lead range, not an exact level, and tests nothing else unless you pay extra for the optional lab test.
Lab-certified results
ETR Laboratories
50+ substances, including lead, copper, arsenic, nitrate, hardness and coliform bacteria
What it can't tell you: It does not test PFAS, and not every result on the panel falls under the lab's accredited scope.
Each card names which of this system’s findings its current certification covers, and which it doesn’t.
As an Amazon Associate, PurityMap earns from qualifying purchases. A product appears here only when a current certification record covers at least one identified concern; every concern stays listed. The retail offer is looked up afterwards and never changes which products appear or their order. Affiliate disclosure.
RAPID CITY (PWS ID SD4600406) is a public water system serving 72,009 people in Rapid City, South Dakota.
RAPID CITY is on record as drawing from surface water. The source shapes which contaminants matter most for this system.
PurityMap's record for RAPID CITY holds 31 findings: 2 detected within the reference and 29 not detected, from 31 evidence records. Every finding links to its source; a substance that was never monitored is shown as pending, not as a pass.
PurityMap does not issue a safety verdict. It publishes RAPID CITY's measured results against each contaminant's benchmark so you can read them in context. Safety depends on the specific finding, your plumbing, and how the water reaches your tap.
The latest published record for RAPID CITY is dated 2026-09-16. Utilities report on regulatory cycles, so results reflect the monitoring period rather than a live reading.
No. It is assessed at the water-system level from RAPID CITY's own monitoring. It does not cover the service line to your building or the plumbing inside it, which can add lead and other metals after the water leaves the system. A tap test is the way to know what reaches your glass.
Perfluorohexanesulfonic acid (PFHxS) and Lead (90th percentile) were detected in this record. Each finding shows its measured value, its reference and its source on this page.
Start with what the record shows: the PFAS findings above list each measured value against its reference. This record cannot show your home's plumbing, so a tap test tells you what reaches your glass. If you decide to treat your water, look for a filter whose certification covers the specific PFAS compounds in your record; the section "Certified for a concern found here" lists only products with a current certification record for these concerns.
Start with what the record shows: the lead findings above list each measured value against its reference. This record cannot show your home's plumbing, so a tap test tells you what reaches your glass. If you decide to treat your water, look for a filter whose certification covers the specific contaminant in your record; the section "Certified for a concern found here" lists only products with a current certification record for these concerns.
Follow Rapid City
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As listed for this system in EPA's records. Your water bill names your supplier.
| Substance | Result | Reference | Sampled | Status | Evidence |
|---|---|---|---|---|---|
| 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS) | < 5 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| 1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS) | < 3 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| 1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS) | < 5 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| 1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS) | < 5 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| 9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS) | < 2 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA) | < 3 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals) | < 5 ng/L | 10 ng/L federal MCL (2024) | 2024-08-29 to 2025-09-03 | Not detected | — |
| N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA) | < 5 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| Nonafluoro-3,6-dioxaheptanoic acid (NFDHA) | < 20 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA) | < 6 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| Perfluorobutanoic acid (PFBA) | < 5 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| Perfluorobutanesulfonic acid (PFBS) | < 3 ng/L | 2,000 ng/L EPA health advisory (screening, not a legal limit) | 2024-08-29 to 2025-09-03 | Not detected | — |
| Perfluorodecanoic acid (PFDA) | < 3 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| Perfluorododecanoic acid (PFDoA) | < 3 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA) | < 3 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| Perfluoroheptanoic acid (PFHpA) | < 3 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| Perfluoroheptanesulfonic acid (PFHpS) | < 3 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| Perfluorohexanoic acid (PFHxA) | < 3 ng/L | 400,000 ng/L Michigan EGLE state MCL (strictest US state) | 2024-08-29 to 2025-09-03 | Not detected | — |
| Perfluorohexanesulfonic acid (PFHxS) | 5.6 ng/L | 10 ng/L federal MCL (2024) | 2024-08-29 to 2025-09-03 | Below limit | View evidence |
| Perfluoro-4-methoxybutanoic acid (PFMBA) | < 3 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| Perfluoro-3-methoxypropanoic acid (PFMPA) | < 4 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| Perfluorononanoic acid (PFNA) | < 4 ng/L | 10 ng/L federal MCL (2024) | 2024-08-29 to 2025-09-03 | Not detected | — |
| Perfluorooctanoic acid (PFOA) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | 2024-08-29 to 2025-09-03 | Not detected | View evidence |
| Perfluorooctanesulfonic acid (PFOS) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | 2024-08-29 to 2025-09-03 | Not detected | View evidence |
| Perfluoropentanoic acid (PFPeA) | < 3 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| Perfluoropentanesulfonic acid (PFPeS) | < 4 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| Perfluorotetradecanoic acid (PFTA) | < 8 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| Perfluorotridecanoic acid (PFTrDA) | < 7 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| Perfluoroundecanoic acid (PFUnA) | < 2 ng/L | No federal or state limit; shown for transparency | 2024-08-29 to 2025-09-03 | Not detected | — |
| Lithium | < 9 µg/L | 10 µg/L EPA health reference level (screening, not a legal limit) | 2024-08-29 to 2025-09-03 | Not detected | — |
| Lead (90th percentile) | 6 µg/L | 15 µg/L federal action level | 2024–2024 monitoring period | Below limit | View evidence |
UCMR5 Analytical Results
UCMR5 Analytical Results: RAPID CITY (SD4600406)
US EPA
State SDWIS Compliance Record
Lead & Copper Rule 90th-percentile: RAPID CITY (SD4600406)
US EPA SDWIS