County · New York
St. Lawrence County, New York: drinking water records
This overview covers 45 ZIP codes and 39 community water systems in St. Lawrence County. It also stands in for 30 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 |
|---|---|---|---|---|---|
| Potsdam Village NY4404397 | 8,312 | 120 | 0 | 2 | 7.8 ppb |
| Massena Village NY4404390 | 16,729 | 95 | 0 | 0 | 1.5 ppb |
| Ogdensburg City NY4404394 | 10,064 | 120 | 2 | 0 | 1.4 ppb |
| Canton Village NY4404381 | 7,055 | 300 | 0 | 0 | 2.8 ppb |
| Gouverneur NY4404385 | 4,263 | 240 | 0 | 0 | 2.3 ppb |
| East Louisville Water District NY4430133 | 3,235 | 0 | 0 | 0 | 1.1 ppb |
| Norfolk Water District NY4404392 | 2,300 | 0 | 0 | 0 | 1 ppb |
| Norwood NY4404393 | 1,685 | 0 | 0 | 0 | 2.6 ppb |
| Star Lake Water District NY4404398 | 1,250 | 0 | 0 | 0 | 2 ppb |
| Waddington Village NY4404400 | 944 | 0 | 0 | 0 | 4.3 ppb |
| Colton Water District NY4404404 | 850 | 0 | 0 | 0 | 2.6 ppb |
| Heuvelton Village NY4404387 | 830 | 0 | 0 | 0 | 2.2 ppb |
| Madrid Water District NY4404389 | 800 | 0 | 0 | 0 | 3.7 ppb |
| Lisbon Water District NY4421088 | 499 | 0 | 0 | 0 | 0 ppb |
| Dekalb Water District NY4430115 | 492 | 0 | 0 | 0 | 7 ppb |
| Hermon Water District NY4404386 | 492 | 0 | 0 | 0 | 4.2 ppb |
| Edwards Water District NY4404384 | 465 | 0 | 0 | 0 | 4.2 ppb |
| Parishville Water District #1 NY4404395 | 450 | 0 | 0 | 0 | 2.6 ppb |
| Morristown Water District NY4404391 | 395 | 0 | 0 | 0 | 3.4 ppb |
| Potsdam Water District No. 1 NY4404399 | 220 | 0 | 0 | 0 | 1 ppb |
| Wanakena Water Company NY4404401 | 200 | 0 | 0 | 0 | 1.8 ppb |
| Helena Water District NY4430165 | 180 | 0 | 0 | 0 | 1 ppb |
| Gouverneur East Side Water District NY4430137 | 165 | 0 | 0 | 0 | 1.3 ppb |
| Gouverneur West Side Water District NY4430138 | 165 | 0 | 0 | 0 | 6 ppb |
| Piercefield Water District NY4404396 | 164 | 0 | 0 | 0 | 0.9 ppb |
ZIP reports in St. Lawrence 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: 12922, 12927, 12965, 12967, 12973, 13613, 13614, 13621, 13623, 13625, 13630, 13633, 13635, 13639, 13645, 13646, 13647, 13649, 13658, 13664, 13666, 13670, 13680, 13681, 13683, 13684, 13687, 13695, 13696, 13697.
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.