Wastewater treatment plants in Colorado
139 facilities · 107 MGD combined flow
Klarifi tracks 139 publicly owned wastewater treatment plants in Colorado with a combined average flow of 107 MGD, serving about 1,676,422 residents. 32 plants treat more than 1 MGD and 1 more than 10 MGD; 67 use lagoon systems and 16 have digesters or biogas infrastructure. The largest is Persigo Wastewater Treatment Plant in Grand Junction at 10.37 MGD. 7 NPDES permits expire this year and 0 next year.
Every plant below links to a profile with average and design flow, the NPDES permit and its expiry, a three-year compliance snapshot and the capital projects planned in its city. Treatment technology and verified contacts are shown with a free Klarifi account.
139 plant locations in Colorado; dot size follows average flow. Boundaries: U.S. Census Bureau.
NPDES permits and renewals in Colorado
Every plant discharges under an NPDES permit that is renewed every five years, usually with tighter limits. The renewal year is the year a plant budgets for upgrades.
Largest wastewater treatment plants in Colorado
| Facility | City | Avg flow (MGD) | Design (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| Persigo Wastewater Treatment Plant | Grand Junction | 10.37 | 12.5 | CO0040053 | Dec 2022 | 1 |
| Greeley WWTP | Greeley | 8.34 | — | COL040258 | Dec 2030 | 13 |
| Big Dry Creek WWTP | Westminster | 6.94 | — | COR901608 | Jun 2029 | 388 |
| Parker Water + Sanitation District - North Water Reclamation Facility | Parker | 4.83 | — | COG072642 | Aug 2018 | 80 |
| Rainbow Park WWTP | Florence | 3.97 | 8.5 | CO0039748 | Feb 2020 | 0 |
| South Ft. Collins Sanit. Dist. | Fort Collins | 3.52 | 4.5 | CO0020737 | Jan 2018 | 1 |
| Steamboat Springs WWTP | Steamboat Springs | 3.46 | 5 | CO0020834 | Dec 2021 | 34 |
| St Vrain Sanitation District | City Of Longmont | 3.34 | 6 | CO0041700 | Nov 2017 | 4 |
| Northglenn WWTP | Brighton | 3.11 | 4.2 | CO0036757 | Dec 2024 | 7 |
| Fort Lupton WWTF | Fort Lupton | 3.02 | 2.75 | CO0021440 | Jun 2023 | 2 |
Treatment technology for each plant is shown with a free Klarifi account. Create one →
Colorado plants by treatment technology
All 139 plants in Colorado
Wastewater treatment in Colorado: questions
Sources and methodology
Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.
Data refreshed October 26, 2026.
Wastewater terms: WWTP · POTW · MGD · NPDES permit · Anaerobic digester · Lift station · all terms
Cite this page
Journalists, researchers and educators are welcome to quote these figures. Please credit Klarifi as the source and link to this page.
Klarifi. “Wastewater treatment plants in Colorado.” Updated October 26, 2026. https://klarifi.io/facilities/coloradoNeed a custom cut of the data for a state, a county or a list of plants? Email info@klarifi.io.