SENTINEL GAP WATER ASSN
PWS ID: WA5376620 · Mattawa, Washington 99349
Population Served
226
Total Violations
59
Health-Based Violations
18
Water Source
Groundwater
System Details
- System Type
- Community
- Owner Type
- Private
- Connections
- 68
- County
- Grant
- School/Daycare
- No
- MCL Violations
- 18
- Monitoring Violations
- 33
- Treatment Tech Violations
- 0
Violation History
Contaminant violations recorded by EPA.
| Contaminant | Category | Count | Latest |
|---|---|---|---|
| Coliform (TCR) | MR | 19 | 2015 |
| Coliform (TCR) | MCL | 18 | 2005 |
| Consumer Confidence Rule | Other | 6 | 2023 |
| Revised Total Coliform Rule | MON | 3 | 2023 |
| Lead and Copper Rule | MR | 2 | 1997 |
| Cadmium | MR | 1 | 1979 |
| Barium | MR | 1 | 1979 |
| Mercury | MR | 1 | 1979 |
| Arsenic | MR | 1 | 1979 |
| Gross Alpha, Excl. Radon and U | MR | 1 | 1979 |
| Chromium | MR | 1 | 1979 |
| Selenium | MR | 1 | 1979 |
| Fluoride | MR | 1 | 1979 |
| Nitrate | MR | 1 | 1979 |
Data Sources: EPA Safe Drinking Water Information System (SDWIS), Q4 2025.
This data is provided for informational purposes only.