How many wastewater treatment plants are there in Colorado?

Klarifi tracks 137 publicly owned wastewater treatment plants in Colorado with a combined average flow of 112 million gallons per day, serving about 1,625,865 residents. 34 of them treat more than 1 MGD and 1 more than 10 MGD.

What is the largest wastewater treatment plant in Colorado?

Persigo Wastewater Treatment Plant in Grand Junction is the largest plant in Colorado by average flow, treating about 11.4 MGD.

What treatment technologies are common in Colorado?

69 of Colorado's plants use lagoon systems and 16 have biogas or anaerobic digestion infrastructure, based on Klarifi's aerial imagery review.

How many NPDES permits in Colorado are up for renewal?

7 permits held by Colorado plants expire in 2026 and 0 in 2027. Renewals typically bring new limits and trigger upgrade projects.

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Wastewater Treatment Plants in Colorado

Name: Wastewater treatment plants in Colorado
Creator: Klarifi
License: https://klarifi.io/terms-of-service

137 facilities · 112 MGD combined flow

Klarifi tracks 137 publicly owned wastewater treatment plants in Colorado with a combined average flow of 112 MGD, serving about 1,625,865 residents. 34 plants treat more than 1 MGD and 1 more than 10 MGD; 69 use lagoon systems and 16 have digesters or biogas infrastructure. The largest is Persigo Wastewater Treatment Plant in Grand Junction at 11.4 MGD. 7 NPDES permits expire this year and 0 next year.

Every plant below links to a profile with average and design flow, treatment technology, the NPDES permit and its expiry, a three-year compliance snapshot and the capital projects planned in its city.

137 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.

All NPDES permits in Colorado →7 permits expiring in 2026 →Find plants near you on the map →

Largest wastewater treatment plants in Colorado

The 25 largest publicly owned wastewater treatment plants in Colorado by average flow, with NPDES permit, expiry, treatment technology and three-year violation count. Source: EPA ICIS-NPDES via Klarifi.
Facility	City	Avg flow (MGD)	Design (MGD)	NPDES permit	Expires	Technology	Violations (3y)
Persigo Wastewater Treatment Plant	Grand Junction	11.4	12.5	CO0040053	Dec 2022	Clarifiers, Aerated lagoons, Uncovered lagoons, Biogas silos	1
Greeley WWTP	Greeley	9.4	—	COL040258	Dec 2030	Clarifiers, Aerated lagoons, Uncovered lagoons, Biogas silos, Biogas balloons, Cooling towers	13
Big Dry Creek WWTP	Westminster	6.9	—	COR901608	Jun 2029	Clarifiers, Biogas silos	388
Parker Water + Sanitation District - North Water Reclamation Facility	Parker	5.1	—	COG072642	Aug 2018	Clarifiers, Biogas silos	75
Rainbow Park WWTP	Florence	4.7	8.5	CO0039748	Feb 2020	Clarifiers	0
South Ft. Collins Sanit. Dist.	Fort Collins	4.23	4.5	CO0020737	Jan 2018	Clarifiers, Carrousels / oxidation ditches, Biogas balloons	1
Fort Lupton WWTF	Fort Lupton	3.86	2.75	CO0021440	Jun 2023	Carrousels / oxidation ditches	2
Northglenn WWTP	Brighton	3.65	4.2	CO0036757	Dec 2024	Clarifiers	10
St Vrain Sanitation District	City Of Longmont	3.55	6	CO0041700	Nov 2017	—	0
Lafayette WWTF	Lafayette	3.03	—	COR900828	Jun 2029	Clarifiers, Biogas silos, Biogas balloons	0
Town Of Windsor Sewarage Treatment Plant	Windsor	2.85	2.8	CO0020320	May 2020	Clarifiers, Aerated lagoons	0
City Of Louisville	Louisville	2.68	3.4	CO0023078	Sep 2016	Clarifiers	3
Arapahoe County Water And Waste Water Authority	Englewood	2.53	3.6	COE015000	Aug 2020	Clarifiers, Uncovered lagoons	0
Steamboat Springs WWTP	Steamboat Springs	2.22	5	CO0020834	Dec 2021	Uncovered lagoons, Biogas silos	27
Breckenridge Sanitation District	Breckenridge	1.96	4.99	CO0021539	Aug 2020	—	0
Hill-N-Park STP	Greeley	1.79	2.88	CO0047287	Dec 2023	Clarifiers, Uncovered lagoons	5
Golden City Of	Jefferson County	1.73	4.8	CO0042170	Sep 2017	Aerated lagoons, Uncovered lagoons	0
Sterling City Of	Sterling	1.64	2.68	CO0026247	Feb 2017	Uncovered lagoons	9
San Juan (formerly Vista) WTP	Pagosa Springs	1.63	—	COG081215	May 2028	Clarifiers, Carrousels / oxidation ditches	84
Berthoud Town Of WWTP	Berthoud	1.61	2	CO0046663	Jul 2020	Clarifiers	16
Aspen Consolidated Sanitation District	Aspen	1.4	3	CO0026387	Apr 2031	Aerated lagoons	10
Delta WWTP	Delta	1.33	—	COR900345	Jun 2029	—	1
Clifton #2 West WWTP	Clifton	1.3	2.5	CO0033791	Mar 2020	Clarifiers, Uncovered lagoons, Carrousels / oxidation ditches	0
Upper Monument Crk Reg WWTF	Colorado Springs	1.17	1.75	CO0042030	Apr 2020	—	39
Woodmen Hills Metro Dist WWTF	Peyton	1.16	1.3	CO0047091	Jan 2020	Uncovered lagoons	0

The 50 largest plants in Colorado →Colorado capital improvement plans →

Colorado plants by treatment technology

Lagoon systems (69)Activated sludge and clarifiers (29)Anaerobic digesters and biogas (16)Oxidation ditches (9)

All 137 plants in Colorado

Facility	City	Flow (MGD)
Persigo Wastewater Treatment Plant	Grand Junction	11.4
Greeley WWTP	Greeley	9.4
Big Dry Creek WWTP	Westminster	6.9
Parker Water + Sanitation District - North Water Reclamation Facility	Parker	5.1
Rainbow Park WWTP	Florence	4.7
South Ft. Collins Sanit. Dist.	Fort Collins	4.23
Fort Lupton WWTF	Fort Lupton	3.86
Northglenn WWTP	Brighton	3.65
St Vrain Sanitation District	City Of Longmont	3.55
Lafayette WWTF	Lafayette	3.03
Town Of Windsor Sewarage Treatment Plant	Windsor	2.85
City Of Louisville	Louisville	2.68
Arapahoe County Water And Waste Water Authority	Englewood	2.53
Steamboat Springs WWTP	Steamboat Springs	2.22
Breckenridge Sanitation District	Breckenridge	1.96
Hill-N-Park STP	Greeley	1.79
Golden City Of	Jefferson County	1.73
Sterling City Of	Sterling	1.64
San Juan (formerly Vista) WTP	Pagosa Springs	1.63
Berthoud Town Of WWTP	Berthoud	1.61
Aspen Consolidated Sanitation District	Aspen	1.4
Delta WWTP	Delta	1.33
Clifton #2 West WWTP	Clifton	1.3
Upper Monument Crk Reg WWTF	Colorado Springs	1.17
Woodmen Hills Metro Dist WWTF	Peyton	1.16
Telluride Regional WWTF	Telluride	1.13
Craig WWTF	Craig	1.09
Regional WWTF	Alamosa	1.09
Harold D Thompson Regional WW Reclamation Facility	Fountain	1.08
Fruita Wastewater Reclamation Facility	Fruita	1.07
Pinery WWTF	Parker	1.04
City Of Trinidad	Trinidad	1.02
Rifle Reg. WW Reclamation Fac.	Rifle	1
Vail WWTP	Vail	1
Upper Thompson WWTP	Estes Park	0.88
Southwest WWTF	Cortez	0.79
City Of Salida WWTP	Salida	0.78
Stonegate Village Metro Dist	Parker	0.74
Lake City Area STP	Lake City	0.72
Las Animas WWTP	Las Animas	0.71
Gypsum WWTF	Gypsum	0.7
Woodland Park City Of	Woodland Park	0.64
Buena Vista Sanitation District WWTF	Buena Vista	0.62
Estes Park Sanitation District	Estes Park	0.6
Evergreen WWTP	Evergreen	0.59
Table Mountain WWTF	Grand Lake	0.59
Low Point WWTP	Johnstown	0.55
Milliken Sanitation District	Milliken	0.53
Mt Cb Water + Sanitation District Water Treatment Plant Expansion	Mount Crested Butte	0.53
Rocky Ford Sewage Lagoons	Rocky Ford	0.52
Black Hawk/central City Sd WWTF	Black Hawk	0.49
West Montrose Sanitation Dist WWTF	Montrose	0.42
Granby Sanitation District WWTF	Granby	0.42
Wray City Of-WTP Clearwell	Wray	0.41
Leadville Sanitation District	Leadville	0.37
Mead, Town Of	Mead	0.33
Hayden Town Of	Hayden	0.33
Monte Vista City Of	Monte Vista	0.32
Southern Ute Indian Tribe	Ignacio	0.31
Hotchkiss WWTP	Hotchkiss	0.27
Georgetown WWTP	Georgetown	0.26
Copper Mountain Consolidated Metro District	Copper Mountain	0.25
Palisade WWTF	Palisade	0.24
Cripple Creek, City Of, WWTP	Cripple Creek	0.24
Idaho Springs City Of	Idaho Springs	0.23
Olathe WWTP	Olathe	0.2
Winter Park Wsd WWTF	Winter Park	0.2
Meeker Sanitation District	Meeker	0.19
Perry Park Wsd	Larkspur	0.18
Julesburg Town Of	Julesburg	0.16
Keenesburg, Town Of	Keenesburg	0.15
Paonia WWTF	Paonia	0.13
Nucla WWTF	Nucla	0.13
Dolores WWTP	Dolores	0.12
Fairplay Sanitation District WWTF	Fairplay	0.12
Silverton Town Of	Silverton	0.12
Kersey, Town Of	Kersey	0.12
Del Norte WWTF	Del Norte	0.11
North La Junta Sd	La Junta	0.11
Mancos Town Of	Mancos	0.11
St. Marys Glacier Wsd	Idaho Springs	0.11
Roaring Fork Wsd WWTF	Carbondale	0.09
Creede WWTF	Creede	0.09
Round Mountain Water And Sanitation District	Westcliffe	0.09
Veterans Center WWTF	Monte Vista	0.09
Sageport Wastewater Treatment Plant	Larkspur	0.09
Antonito Town Of	Antonito	0.08
Morrison Creek Metro Water &	Oak Creek	0.07
Costilla County W&s System	San Luis	0.07
La Veta Town Of	La Veta	0.06
Cucharas Swd	La Veta	0.06
Loma Linda San Dist WWTF	Durango	0.06
Walden, Town Of	Walden	0.06
Hot Sulphur Spr. WWTP	Hot Sulphur Springs	0.06
La Jara WWTP	La Jara	0.05
Collbran WWTP	Collbran	0.05
Spring Valley Sd WWTF	Glenwood Springs	0.05
Mountain Wsd	Conifer	0.05
Crawford WWTF	Crawford	0.05
Kiowa Town Of-Chlorinator For Lower West Well	Kiowa	0.04
Victor City Of	Victor	0.04
Kit Carson WWTF	Kit Carson	0.04
Debeque Town Of	De Beque	0.04
Red Cliff Town Of	Red Cliff	0.04
Teller County WW Utility Board	Divide	0.04
Tabernash Meadows Wsd WWTF	Tabernash	0.04
Upper Valley Sanitation Dist.	Bayfield	0.03
Lake Eldora Wsd WWTF	Nederland	0.03
Will-O-Wisp Md	Bailey	0.03
Fort Garland Water & San Dist	Fort Garland	0.03
Steamboat Lake Wsd	Steamboat Springs	0.03
Aspen Park Metropolitan District	Conifer	0.02
Eldorado Springs WWTF	Eldorado Springs	0.02
Grand Mesa WWTF	Mesa	0.02
Conifer Metropolitan District	Conifer	0.02
Stagecoach State Park	Oak Creek	0.02
Florissant Wsd	Florissant	0.02
Galeton Water & San District	Galeton	0.01
Cokedale WWTF	Cokedale	0.01
Redstone Wsd WWTF	Redstone	0.01
Steamboat Lake State Park	Clark	0.0099
Peyton High School	Peyton	0.0098
Clear Creek Regional WWTP	Evergreen	0.0064
Edith Wolford Elem School WWTF	Black Forest	0.0027
Gilpin County School District Re-1	Blackhawk	0.001
Campo WWTF	Campo	—
Fowler Town Of-Cl2 For North Springs	Fowler	—
Jd Phillips Water Reclamation Facility	Colorado Springs	—
Las Vegas St WWTF	Colorado Springs	—
Lochbuie Town Of	Lochbuie	—
Mulberry WWTP	Fort Collins	—
Penrose WWTF	Penrose	—
Sand Creek Water Reuse Facilty	Aurora	—
Snowmass Water And San Dist	Snowmass Village	—
Somerset WWTF	Somerset	—
Spring Valley Ranch WWTF	Englewood	—
Upper Eagle Regional Water Authority Plant	Avon	—

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 11, 2026.

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