Wastewater treatment plants in Colorado
138 facilities · 261 MGD combined flow
Klarifi tracks 138 publicly owned wastewater treatment plants in Colorado with a combined average flow of 261 MGD, serving about 3,623,183 residents. 35 plants treat more than 1 MGD and 2 more than 10 MGD; 69 use lagoon systems and 17 have digesters or biogas infrastructure. The largest is Metro Wastewater Reclamation Dist/trigen in Denver at 148 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.
138 plant locations in Colorado; dot size follows average flow.
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) |
|---|---|---|---|---|---|---|
| Metro Wastewater Reclamation Dist/trigen | Denver | 148 | — | COL026638 | Dec 2030 | 4 |
| Persigo Wastewater Treatment Plant | Grand Junction | 11.4 | 12.5 | CO0040053 | Dec 2022 | 1 |
| Greeley WWTP | Greeley | 9.4 | — | COL040258 | Dec 2030 | 13 |
| Big Dry Creek WWTP | Westminster | 6.9 | — | COR901608 | Jun 2029 | 388 |
| Parker Water + Sanitation District - North Water Reclamation Facility | Parker | 5.1 | — | COG072642 | Aug 2018 | 75 |
| Rainbow Park WWTP | Florence | 4.7 | 8.5 | CO0039748 | Feb 2020 | 0 |
| South Ft. Collins Sanit. Dist. | Fort Collins | 4.23 | 4.5 | CO0020737 | Jan 2018 | 1 |
| Fort Lupton WWTF | Fort Lupton | 3.86 | 2.75 | CO0021440 | Jun 2023 | 2 |
| Northglenn WWTP | Brighton | 3.65 | 4.2 | CO0036757 | Dec 2024 | 10 |
| St Vrain Sanitation District | City Of Longmont | 3.55 | 6 | CO0041700 | Nov 2017 | 0 |
Treatment technology for each plant is shown with a free Klarifi account. Create one →
Colorado plants by treatment technology
All 138 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 September 14, 2026.