No health-based violations on EPA record since 2016.
Serves about 2,190 people (876 connections) with surface water from its own intake.
From EPA's record for SD4600112. PurityMap is independent of Tri-County Rural Water System.
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No health-based violations in the last 10 years, from EPA's SDWIS compliance database.
EPA required this system to test for 30 unregulated and emerging contaminants, from January 2025 to July 2025.
| Contaminant | Result | Limit | Status | Sampled | Source |
|---|---|---|---|---|---|
| Lithium | 64.8 µg/L | 10 µg/L EPA health reference level (screening, not a legal limit)Screening level, not a legal limit | Above the referenced health-based guidance value | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| 11-Chloroeicosafluoro-3-oxaundecane-1-sulfonic acid (11Cl-PF3OUdS) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| 1H, 1H, 2H, 2H-perfluorodecane sulfonic acid (8:2 FTS) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| 1H, 1H, 2H, 2H-perfluorohexane sulfonic acid (4:2 FTS) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| 1H, 1H, 2H, 2H-perfluorooctane sulfonic acid (6:2 FTS) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| 9-Chlorohexadecafluoro-3-oxanone-1-sulfonic acid (9Cl-PF3ONS) | < 2 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals) | < 5 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA) | < 6 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Nonafluoro-3,6-dioxaheptanoic acid (NFDHA) | < 20 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluoro-3-methoxypropanoic acid (PFMPA) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluoro-4-methoxybutanoic acid (PFMBA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluorobutanesulfonic acid (PFBS) | < 3 ng/L | 2,000 ng/L EPA health advisory (screening, not a legal limit)Screening level, not a legal limit | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluorobutanoic acid (PFBA) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluorodecanoic acid (PFDA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluorododecanoic acid (PFDoA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluoroheptanesulfonic acid (PFHpS) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluoroheptanoic acid (PFHpA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluorohexanesulfonic acid (PFHxS) | < 3 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluorohexanoic acid (PFHxA) | < 3 ng/L | 400,000 ng/L Michigan EGLE state MCL (strictest US state) | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluorononanoic acid (PFNA) | < 4 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluorooctanesulfonic acid (PFOS) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluorooctanoic acid (PFOA) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluoropentanesulfonic acid (PFPeS) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluoropentanoic acid (PFPeA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluorotetradecanoic acid (PFTA) | < 8 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluorotridecanoic acid (PFTrDA) | < 7 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
| Perfluoroundecanoic acid (PFUnA) | < 2 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2025-01-06 to 2025-07-15 | UCMR5 Analytical Results: TRI-COUNTY RURAL WATER SYSTEM (SD4600112) |
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
Turnaround: 5 minutes
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
Environmental Testing and Research Laboratories (ETR Labs), Leominster, MA · ISO/IEC 17025:2017, ANAB certificate AT-2638 · 2–4 business days after the lab receives it
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.
Get PurityMap updates about this water system.
Follow this water →Tri-County Rural Water System's phone number on EPA record is 6059647766. Its mailing address is PO BOX 490, EAGLE BUTTE, SD 57625.
According to EPA's record, Tri-County Rural Water System uses surface water from its own intake.
No health-based violations on EPA record since 2016. EPA also lists 2 missed or late tests or reports in 10 years. The record comes from EPA's SDWIS compliance database.
The 90th-percentile lead result in Tri-County Rural Water System's latest lead and copper round, which ended in December 2023, was 4 µg/L, below the federal action level of 15 µg/L.
PurityMap has no verified website for Tri-County Rural Water System. Its phone number on EPA record is 6059647766. Its mailing address on EPA record is PO BOX 490, EAGLE BUTTE, SD 57625. Your water bill lists the ways to contact your supplier and pay. PurityMap does not take payments.