County · Maryland
Montgomery County, Maryland: drinking water records
This overview covers 48 ZIP codes and 5 community water systems in Montgomery County. It also stands in for 4 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 |
|---|---|---|---|---|---|
| Washington Suburban Sanitary Commission MD0150005 | 1,900,000 | 240 | 2 | 0 | 0 ppb |
| City of Rockville MD0150003 | 52,000 | 120 | 4 | 0 | 0 ppb |
| Town of Poolesville MD0150002 | 6,005 | 570 | 8 | 0 | 5 ppb |
| Fairland Crossing Apartments MD0150102 | 1,248 | 0 | 0 | 0 | not reported |
| Whitley Park Condominiums MD0150101 | 256 | 0 | 0 | 0 | not reported |
ZIP reports in Montgomery 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: 20838, 20839, 20842, 20862.
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.