County · Colorado
Boulder County, Colorado: drinking water records
This overview covers 18 ZIP codes and 42 community water systems in Boulder County. It also stands in for 1 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 |
|---|---|---|---|---|---|
| Boulder City of CO0107152 | 166,080 | 240 | 0 | 2 | 2 ppb |
| Louisville City of CO0107487 | 20,975 | 240 | 0 | 2 | 0 ppb |
| Superior Md No 1 CO0107725 | 17,900 | 120 | 0 | 2 | 0 ppb |
| Longmont City of CO0107485 | 104,178 | 120 | 0 | 0 | 1.6 ppb |
| Erie Town of CO0162255 | 47,444 | 120 | 0 | 0 | 2.6 ppb |
| Lafayette City of CO0107473 | 28,700 | 240 | 0 | 0 | 2 ppb |
| Left Hand WD CO0107471 | 20,280 | 240 | 0 | 0 | 1 ppb |
| Arbordale Acres MHP CO0107118 | 901 | 0 | 0 | 1 | 0 ppb |
| San Lazaro Mfctd Housing Community CO0107701 | 844 | 0 | 0 | 2 | 0 ppb |
| Allenspark WSD CO0107115 | 340 | 0 | 0 | 3 | 4 ppb |
| Jamestown Town of CO0107401 | 280 | 0 | 0 | 4 | 2 ppb |
| Sans Souci Cooperative CO0107702 | 150 | 0 | 0 | 15 | 2.5 ppb |
| Spring Valley Mutual Wa CO0107719 | 100 | 0 | 0 | 2 | 1 ppb |
| Table Mesa Village MHP CO0107733 | 75 | 0 | 0 | 11 | 0 ppb |
| Longs Peak WD CO0107486 | 3,200 | 0 | 0 | 0 | 2 ppb |
| Lyons Town of CO0107496 | 2,990 | 0 | 0 | 0 | 0 ppb |
| Nederland Town of CO0107538 | 2,406 | 0 | 0 | 0 | 1 ppb |
| Boulder Meadows MHP CO0107179 | 1,657 | 0 | 0 | 0 | 0 ppb |
| Pine Brook Hills WD CO0107610 | 1,100 | 0 | 0 | 0 | 0 ppb |
| Mile Hi Water INC Hauler CO0107510 | 1,000 | 0 | 0 | 3 | not reported |
| Boulder Ridge MHP CO0107153 | 897 | 0 | 0 | 0 | 0 ppb |
| Baseline WD CO0107135 | 820 | 0 | 0 | 0 | 0 ppb |
| Countryside of Longmont CO0107184 | 775 | 0 | 0 | 0 | 0 ppb |
| Hoover Hills WSD CO0107352 | 662 | 0 | 0 | 0 | 0 ppb |
| St Vrain MHP LLC CO0107724 | 544 | 0 | 0 | 0 | 0 ppb |
ZIP reports in Boulder 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: 80471.
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.