No open health-based violations on EPA record in the last 10 years; latest legal-limit breach in the period starting August 2023.
Serves about 8,410 people (2,725 connections) with groundwater from its own wells.
From EPA's record for WA5306029. PurityMap is independent of Yak Co.
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1 health-based violation in the last 10 years, from EPA's SDWIS compliance database.
| Period | Contaminant | Measured | Legal limit | EPA status |
|---|---|---|---|---|
| From August 2023 | E. coli | – | – | Resolved |
EPA required this system to test for 30 unregulated and emerging contaminants, from June 2024 to June 2025.
| Contaminant | Result | Limit | Status | Sampled | Source |
|---|---|---|---|---|---|
| Lithium | 12.9 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 | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| 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 | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| 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 | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| 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 | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| 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 | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| 4,8-Dioxa-3H-perfluorononanoic acid (ADONA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| 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 | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Hexafluoropropylene oxide dimer acid (HFPO-DA) (GenX chemicals) | < 5 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| N-ethyl perfluorooctanesulfonamidoacetic acid (NEtFOSAA) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| N-methyl perfluorooctanesulfonamidoacetic acid (NMeFOSAA) | < 6 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Nonafluoro-3,6-dioxaheptanoic acid (NFDHA) | < 20 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluoro (2-ethoxyethane) sulfonic acid (PFEESA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluoro-3-methoxypropanoic acid (PFMPA) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluoro-4-methoxybutanoic acid (PFMBA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| 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 | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluorobutanoic acid (PFBA) | < 5 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluorodecanoic acid (PFDA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluorododecanoic acid (PFDoA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluoroheptanesulfonic acid (PFHpS) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluoroheptanoic acid (PFHpA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluorohexanesulfonic acid (PFHxS) | < 3 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluorohexanoic acid (PFHxA) | < 3 ng/L | 400,000 ng/L Michigan EGLE state MCL (strictest US state) | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluorononanoic acid (PFNA) | < 4 ng/L | 10 ng/L federal MCL (2024) | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluorooctanesulfonic acid (PFOS) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluorooctanoic acid (PFOA) | < 4 ng/L | 4.0 ng/L federal MCL (2024) | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluoropentanesulfonic acid (PFPeS) | < 4 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluoropentanoic acid (PFPeA) | < 3 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluorotetradecanoic acid (PFTA) | < 8 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluorotridecanoic acid (PFTrDA) | < 7 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
| Perfluoroundecanoic acid (PFUnA) | < 2 ng/L | No federal or state limit; shown for transparency | Not detected above the reporting limit | 2024-06-24 to 2025-06-04 | UCMR5 Analytical Results: YAK CO - TERRACE HEIGHTS (WA5306029) |
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 →According to EPA's record, Yak Co uses groundwater from its own wells.
EPA's record shows 1 health-based violation for Yak Co in the 10 years to July 9, 2026. No open health-based violations on EPA record in the last 10 years. The latest legal-limit breach on record was in the period starting August 2023. EPA also lists 24 missed or late tests or reports in 10 years. The record comes from EPA's SDWIS compliance database.
Lead was not detected at the 90th percentile of tap samples in Yak Co's latest lead and copper round, which ended in December 2023. The federal action level is 15 µg/L.
PurityMap has no verified website for Yak Co. Its mailing address on EPA record is 128 N 2Nd-4th Floor Courthouse, Yakima, WA 98901. Your water bill lists the ways to contact your supplier and pay. PurityMap does not take payments.