Hydrohistorian
Water providers in Boulder County, Colorado
Who is my water provider?
Type a Colorado address, or use your location. This names the community water systems whose EPA service-area boundary contains that point.
Blue is a boundary a utility or county traced; amber is one EPA modelled from census places. Click an area for the system. Systems with no boundary on file are in the table but not on the map.
Towns in Boulder County
Each names the systems whose service area covers it.
- Altona
- Boulder
- Erie
- Firestone
- Frederick
- Gunbarrel
- Jamestown
- Lafayette
- Leyner
- Longmont
- Louisville
- Lyons
- Nederland
- Niwot
- Paragon Estates
- Pine Brook Hill
- Superior
- Ward
Every community water system in Boulder County
| System | Serves | Source | Service area | Water district |
|---|---|---|---|---|
| City of Boulder | 166,080 | Surface water | traced | Boulder Creek |
| City of Longmont | 104,178 | Surface water | traced | St. Vrain Creek |
| Town of Erie | 47,444 | Surface water | traced | Boulder Creek |
| City of Lafayette | 28,700 | Surface water | traced | Boulder Creek |
| City of Louisville | 20,975 | Surface water | traced | Boulder Creek |
| Left Hand Water District | 20,280 | Surface water | traced | Boulder Creek |
| Superior Md No. 1 | 17,900 | Surface water | traced | Boulder Creek |
| Longs Peak Water District | 3,200 | Surface water | modelled | St. Vrain Creek |
| Town of Lyons | 2,990 | Purchased surface water | traced | St. Vrain Creek |
| Town of Nederland | 2,406 | Surface water | traced | Boulder Creek |
| Boulder Meadows Mobile Home Park | 1,657 | Purchased surface water | modelled | St. Vrain Creek |
| Pine Brook Hills Water District | 1,100 | Surface water | traced | Boulder Creek |
| Mile Hi Water Inc. Hauler 1 open health-based | 1,000 | Purchased surface water | modelled | Boulder Creek |
| Arbordale Acres Mobile Home Park | 901 | Purchased surface water | none on file | — |
| Boulder Ridge Mobile Home Park | 897 | Purchased surface water | none on file | — |
| San Lazaro Mfctd Housing Community | 844 | Surface water | modelled | Boulder Creek |
| Baseline Water District | 820 | Purchased surface water | traced | Boulder Creek |
| Hoover Hills Water & Sanitation District | 662 | Purchased surface water | traced | Boulder Creek |
| Shannon Water & Sanitation District | 450 | Groundwater | traced | Boulder Creek |
| Skylark Mobile Home Community | 342 | Purchased surface water | none on file | — |
| Allenspark Water & Sanitation District | 340 | Surface water | traced | St. Vrain Creek |
| Eldorado Municipal System | 308 | Groundwater | modelled | Boulder Creek |
| East Boulder County Water District | 300 | Purchased surface water | traced | Boulder Creek |
| Town of Jamestown | 280 | Surface water | traced | St. Vrain Creek |
| Grand Meadow of Longmont Mobile Home Park | 255 | Purchased surface water | none on file | — |
| Lefthand Water & Sanitation District Lake Pines | 250 | Purchased surface water | modelled | St. Vrain Creek |
| Olde Stage Water District | 250 | Groundwater | traced | St. Vrain Creek |
| Town of Ward | 230 | Groundwater | traced | St. Vrain Creek |
| Mountain View Mobile Home Park | 211 | Purchased surface water | none on file | — |
| Lafayette Gardens | 207 | Purchased surface water | none on file | — |
| Sans Souci Cooperative 3 open health-based | 150 | Groundwater under the influence of surface water | modelled | Boulder Creek |
| Spring Valley Mutual Water Association | 100 | Groundwater | modelled | Boulder Creek |
| Meadow Mountain Water Supply | 76 | Surface water | none on file | — |
| Lark Meadows Water Association | 75 | Groundwater | modelled | Boulder Creek |
| Lmp Coop Mobile Home Park | 75 | Purchased surface water | none on file | — |
| Table Mesa Village Mobile Home Park | 75 | Groundwater under the influence of surface water | modelled | Boulder Creek |
| Grace Mar Wua | 50 | Groundwater | none on file | — |
| Maple Grove Water District | 35 | Groundwater | modelled | Boulder Creek |
Common questions
How many water providers are in Boulder County, Colorado?
38 community water systems serve Boulder County, Colorado. The largest is City of Boulder, which reports serving 166,080 people.
Who is my water provider in Boulder County?
It depends on your address: 38 community systems serve parts of Boulder County. Enter an address in the lookup on this page and it will name the systems whose EPA service-area boundary contains that point.
Why is a system in Boulder County missing from the map?
9 of the 38 systems here have no service-area boundary in EPA's file, so they cannot be drawn. They are still in the table on this page, with their source and compliance record.
Nearby counties
Systems and counties from EPA SDWIS federal reporting, fetched 2026-09-08; boundaries from EPA's Community Water System Service Area Boundaries (v3, 2026). A county row here is the county SDWIS files for the system, which is where it serves customers, not necessarily where its intakes are. Report a problem →