County · Missouri
Washington County, Missouri: drinking water records
This overview covers 10 ZIP codes and 12 community water systems in Washington County. It also stands in for 5 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 |
|---|---|---|---|---|---|
| Mineral Point PWS MO4011123 | 231 | 0 | 0 | 2 | 2.1 ppb |
| Potosi PWS MO6010659 | 2,527 | 0 | 0 | 0 | 1.6 ppb |
| Potosi East MO6069096 | 900 | 0 | 0 | 0 | 4.4 ppb |
| Laguna Tres Subdivision TX1110019 | 669 | 0 | 0 | 0 | 0 ppb |
| Laguna Vista Subdivision TX1110095 | 651 | 0 | 0 | 0 | 4.7 ppb |
| Washington County Pwsd 1 MO6024633 | 503 | 0 | 0 | 0 | 1.5 ppb |
| Irondale PWS MO6010401 | 420 | 0 | 0 | 0 | 0.7 ppb |
| Mo American Rogue Creek Utilities MO4036318 | 276 | 0 | 0 | 0 | 2 ppb |
| Anthonies Mill Resort Subdivision MO4036311 | 214 | 0 | 0 | 0 | 0 ppb |
| Washington County Pwsd 2 MO4021447 | 175 | 0 | 0 | 0 | 1.3 ppb |
| Caledonia PWS MO4010003 | 130 | 0 | 0 | 0 | 0 ppb |
| The Legacy Ranch MO4071640 | 25 | 0 | 0 | 0 | 0 ppb |
ZIP reports in Washington 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: 63030, 63071, 63626, 63630, 63674.
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.