County · Oregon
Grant County, Oregon: drinking water records
This overview covers 11 ZIP codes and 8 community water systems in Grant County. It also stands in for 2 ZIP codes whose utility has too little EPA data for a page of its own.
System population figures are summed from EPA registry records and can overlap where wholesalers and retail systems serve the same people. They are not a Census county-population estimate.
Water systems with the most complete records
| Water system | People served | PFAS survey results | PFAS found | Health-based violations | Lead, 9 in 10 homes at or below |
|---|---|---|---|---|---|
| Canyon City Water Department OR4100165 | 666 | 0 | 0 | 1 | 1.9 ppb |
| Monument, City of OR4100541 | 115 | 0 | 0 | 7 | 0.9 ppb |
| John Day, City of OR4100410 | 1,617 | 0 | 0 | 0 | 1.4 ppb |
| Prairie City OR4100673 | 841 | 0 | 0 | 0 | 1.4 ppb |
| Mount Vernon, City of OR4100546 | 510 | 0 | 0 | 0 | 1.3 ppb |
| Seneca, City of OR4100807 | 200 | 0 | 0 | 0 | 2.3 ppb |
| Long Creek, City of OR4100490 | 173 | 0 | 0 | 0 | 0.5 ppb |
| Dayville, City of OR4100253 | 155 | 0 | 0 | 0 | 1.3 ppb |
ZIP reports in Grant County
No ZIP report in this county is published yet.
These ZIP codes are covered by this overview because their utility has too little EPA data for a separate page: 97817, 97848.
Sources and scope
EPA UCMR 5 occurrence data, samples collected 2023-01-03 – 2026-06-17, final release, August 2026 (file dated Aug 28, 2026); EPA SDWIS via ECHO, 2026Q2 extract (file dated Jul 9, 2026); EPA service-area boundaries v3.0; Census 2020 ZCTAs. Page generated 2026-09-03.
Counts cover the systems that report this county to EPA. A water system may cross county lines. "Found" means at least one result at or above the laboratory reporting level; it is not a compliance finding.