How many wastewater treatment plants are there in Iowa?

Klarifi tracks 747 publicly owned wastewater treatment plants in Iowa with a combined average flow of 269 million gallons per day, serving about 1,656,172 residents. 45 of them treat more than 1 MGD and 4 more than 10 MGD.

What is the largest wastewater treatment plant in Iowa?

Water Pollution Control Facility in Cedar Rapids is the largest plant in Iowa by average flow, treating about 39.59 MGD.

What treatment technologies are common in Iowa?

624 of Iowa's plants use lagoon systems and 71 have biogas or anaerobic digestion infrastructure, based on Klarifi's aerial imagery review.

How many NPDES permits in Iowa are up for renewal?

71 permits held by Iowa plants expire in 2026 and 106 in 2027. Renewals typically bring new limits and trigger upgrade projects.

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Wastewater treatment plants in Iowa

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

747 facilities · 269 MGD combined flow

Klarifi tracks 747 publicly owned wastewater treatment plants in Iowa with a combined average flow of 269 MGD, serving about 1,656,172 residents. 45 plants treat more than 1 MGD and 4 more than 10 MGD; 624 use lagoon systems and 71 have digesters or biogas infrastructure. The largest is Water Pollution Control Facility in Cedar Rapids at 39.59 MGD. 71 NPDES permits expire this year and 106 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. Showing facilities 1–200 of 747 by average flow — browse the rest with the page links below.

744 plant locations in Iowa; dot size follows average flow. Boundaries: U.S. Census Bureau.

NPDES permits and renewals in Iowa

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 Iowa →71 permits expiring in 2026 →106 permits expiring in 2027 →102 permits expiring in 2028 →Find plants near you on the map →

Largest wastewater treatment plants in Iowa

The 10 largest publicly owned wastewater treatment plants in Iowa by average flow, with NPDES permit, expiry and three-year violation count. Source: EPA ICIS-NPDES via Klarifi.
Facility	City	Avg flow (MGD)	Design (MGD)	NPDES permit	Expires	Violations (3y)
Water Pollution Control Facility	Cedar Rapids	39.59	86.95	IA0042641	Aug 2030	15
Davenport Wastewater Treatment Plant	Davenport	25.36	40	IA0043052	Jun 2026	0
City Of Sioux City STP	Sioux City	14.01	28.73	IA0043095	Jan 2031	10
Fort Dodge City Of STP	Fort Dodge	11.42	21.6	IA0044849	Dec 2030	0
Iowa City, City Of (south) STP	Iowa City	8.98	43.3	IA0070866	Jul 2030	11
Council Bluffs City Of STP	Council Bluffs	8.21	17.9	IA0036641	Aug 2031	0
Clinton WWTP	Clinton	6.52	17	IA0035947	Jun 2031	12
Burlington, City Of (wwtp)	Burlington	5.79	28.3	IA0043079	Jan 2027	4
Mason WWTP	Mason City	5.13	—	IA0077305	May 2029	6
Cedar Falls City Of STP	Cedar Falls	4.83	21.6	IA0036633	Dec 2029	0

Treatment technology for each plant is shown with a free Klarifi account. Create one →

The 50 largest plants in Iowa →EPA enforcement actions in Iowa →Iowa capital improvement plans →

Iowa plants by treatment technology

Lagoon systems (625)Activated sludge and clarifiers (83)Anaerobic digesters and biogas (71)Oxidation ditches (17)

All 747 plants in Iowa

Facility	City	Flow (MGD)
Water Pollution Control Facility	Cedar Rapids	39.59
Davenport Wastewater Treatment Plant	Davenport	25.36
City Of Sioux City STP	Sioux City	14.01
Fort Dodge City Of STP	Fort Dodge	11.42
Iowa City, City Of (south) STP	Iowa City	8.98
Council Bluffs City Of STP	Council Bluffs	8.21
Clinton WWTP	Clinton	6.52
Burlington, City Of (wwtp)	Burlington	5.79
Mason WWTP	Mason City	5.13
Cedar Falls City Of STP	Cedar Falls	4.83
City Of Muscatine Water & Resource Recovery Facility	Muscatine	3.89
Ottumwa City Of STP	Ottumwa	3.24
City Of Boone Water Pollution Control	Boone	3.05
Coralville WWTP	Coralville	2.98
Iowa Great Lakes Sanitary District WWTP	Milford	2.5
Storm Lake WWTP	Storm Lake	2.45
Newton City Of STP	Newton	2.43
West Liberty City Of STP	West Liberty	2.41
City Of Emmetsburg Treatment Plant	Emmetsburg	2.38
City Of Pella	Pella	2.36
North Liberty WWTP	North Liberty	2.03
Indianola Water Resource Recovery Facility	Indianola	1.96
Eagle Grove, City Of STP	Eagle Grove	1.93
Spencer, City Of	Spencer	1.75
Fredricksburg WWTP	Fredericksburg	1.7
Keokuk City Of STP	Keokuk	1.7
Osceola WWTP South	Osceola	1.68
Fort Madison City Of STP	Fort Madison	1.65
Washington City Of STP	Washington	1.65
Waverly WWTP	Waverly	1.42
Oelwein WWTP	Oelwein	1.4
Knoxville City Of STP	Knoxville	1.39
Nevada City Of WWTP	Nevada	1.37
Webster City WWTP	Webster City	1.36
Grinnell, City Of STP	Grinnell	1.35
Independence WWTP	Independence	1.31
Creston City Of STP	Creston	1.25
Winterset City Of STP	Winterset	1.16
Mount Pleasant WWTP	Mount Pleasant	1.13
Vinton WWTP	Vinton	1.11
City Of Shenandoah STP	Shenandoah	1.1
Perry WWTP	Perry	1.07
Estherville WWTP	Estherville	1.05
Carroll WWTP	Carroll	1.04
Iowa Falls WWTP	Iowa Falls	1.02
City Of Sioux Center STP	Sioux Center	0.97
Red Oak City Of STP	Red Oak	0.96
Eldridge City Of STP (south Slope)	Eldridge	0.96
Fairfield City Of STP	Fairfield	0.93
Story City City Of STP	Story City	0.93
Decorah City Of STP	Decorah	0.92
Sheldon Wastewater Plant	Sheldon	0.9
Orange City City Of STP	Orange City	0.85
Denison Municipal Utilities WWTP	Denison	0.84
Dewitt WWTP	Dewitt	0.82
Anamosa WWTP	Anamosa	0.79
Adel WWTP	Adel	0.77
Algona City Of STP	Algona	0.72
Humboldt City Of STP	Humboldt	0.72
Waukon City Of STP	Waukon	0.71
Oskaloosa SW STP	Oskaloosa	0.71
Ogden City Of STP	Ogden	0.7
Atlantic City Of STP	Atlantic	0.69
Forest City City Of STP	Forest City	0.69
Oskaloosa NE WWTP	Oskaloosa	0.69
Chariton City Of STP	Chariton	0.67
Clarinda City Of STP	Clarinda	0.65
Jefferson WWTP	Jefferson	0.65
Manchester WWTP	Manchester	0.64
Harlan City Of STP	Harlan	0.62
Huxley City Of STP	Huxley	0.61
Sanborn WWTP	Sanborn	0.6
Eldora WWTP	Eldora	0.59
Ackley WWTP	Ackley	0.59
Dyersville WWTP	Dyersville	0.55
Cresco WWTP	Cresco	0.53
Centerville City Of STP (east)	Centerville	0.52
Tiffin WWTP	Tiffin	0.52
Roland City Of STP	Roland	0.51
Monticello WWTP	Monticello	0.5
Colfax City Of STP	Colfax	0.5
Carlisle City Of STP	Carlisle	0.5
West Branch City Of STP	West Branch	0.49
Springville WWTP	Springville	0.49
City Of Solen Treatment Plant	Solon	0.49
Corydon City Of STP	Corydon	0.47
Corning City Of STP	Corning	0.47
Walcott City Of STP (south)	Walcott	0.45
Williamsburg City Of STP	Williamsburg	0.44
Toledo Wastewater Treatment Facility	Toledo	0.43
Asbury City Of STP	Asbury	0.42
Lamoni WWTP	Lamoni	0.42
Stuart WWTP	Stuart	0.41
Wilton City Of STP	Wilton	0.41
Osage City Of STP	Osage	0.41
Mitchellville Water Supply	Mitchellville	0.4
Tipton WWTP (west)	Tipton	0.39
Tama City Of STP	Tama	0.39
Hampton WWTP	Hampton	0.38
Leclaire City Of STP	Le Claire	0.37
West Union City Of STP	West Union	0.37
Reinbeck Water Supply	Reinbeck	0.35
Belle Plaine City Of STP	Belle Plaine	0.35
Panora WWTP	Panora	0.35
Hudson WWTP	Hudson	0.35
Belmond City Of STP	Belmond	0.34
Missouri Valley City Of STP	Missouri Valley	0.34
Earlham City Of STP	Earlham	0.34
Sibley City Of STP	Sibley	0.33
Garner WWTP	Garner	0.33
Prairie City, City Of STP	Prairie City	0.32
Shellsburg WWTP	Shellsburg	0.32
Rockwell City WWTP	Rockwell City	0.32
Albia City Of STP (north)	Albia	0.32
Blue Grass City Of STP	Blue Grass	0.32
Postville City Of STP	Postville	0.31
Gilbert, City Of STP	Gilbert	0.31
Marengo City Of STP	Marengo	0.31
Allison City Of STP	Allison	0.31
Kalona City Of STP	Kalona	0.31
Clarence WWTP	Clarence	0.3
Lone Tree South WWTP	Lone Tree	0.3
Center Point, City Of STP (south)	Center Point	0.3
Rockford WWTP	Rockford	0.29
Sumner City Of STP	Sumner	0.29
Primghar Municipal Light Plant	Primghar	0.29
Fairfax WWTP	Fairfax	0.28
Dysart City Of STP	Dysart	0.28
Rock Rapids City Of STP	Rock Rapids	0.28
City Of Ponahontas WTP	Pocahontas	0.28
Newhall WWTP	Newhall	0.28
Denver WWTP	Denver	0.28
Lake Mills City Of STP	Lake Mills	0.28
Monroe City Of STP (west)	Monroe	0.27
Hartley WWTP	Hartley	0.27
La Porte City WWTP	La Porte City	0.27
Sheffield WWTP	Sheffield	0.27
Manly WWTP	Manly	0.27
Buffalo City Of STP	Buffalo	0.27
Lake City WWTP	Lake City	0.27
Madrid WWTP	Madrid	0.26
Dumont City Of STP	Dumont	0.26
New London WWTP	New London	0.26
Tripoli City Of STP	Tripoli	0.26
Woodward City Of STP	Woodward	0.26
Slater City Of STP	Slater	0.26
Guttenberg WWTP	Guttenberg	0.26
Pleasantville Water Works	Pleasantville	0.26
Alta WWTP	Alta	0.25
Centerville City Of STP (west)	Centerville	0.25
Granger WWTP	Granger	0.25
Dallas Center City Of STP	Dallas Center	0.25
City Of Wapello Wastewater Treatment Plant	Wapello	0.25
Atkins City Of STP	Atkins	0.25
Columbus Junction City Of STP	Columbus Junction	0.24
Winfield WWTP	Winfield	0.24
Hospers City Of STP	Hospers	0.24
Bloomfield WWTP (main)	Bloomfield	0.24
Sac City WWTP	Sac City	0.24
Farley City Of STP	Farley	0.24
Holstein WWTP	Holstein	0.23
State Center City Of STP	State Center	0.23
Lime Springs WWTP	Lime Springs	0.23
Winthrop City Of STP	Winthrop	0.23
Mount Vernon City Of STP	Mount Vernon	0.22
Onawa City Of STP	Onawa	0.22
Wellman City Of STP	Wellman	0.22
Audubon City Of STP	Audubon	0.22
Nashua WWTP	Nashua	0.22
Lake View City Of STP	Lake View	0.21
Sac And Fox Settlement Lagoon	Tama	0.21
Birmingham City Of STP	Birmingham	0.21
Park View Water Co	Eldridge	0.21
Sigourney East WWTP	Sigourney	0.21
Hull City Of STP	Hull	0.21
Northwood City Of STP	Northwood	0.21
Parkersburg City Of STP	Parkersburg	0.21
Stanwood WWTP	Stanwood	0.21
Baxter WWTP	Baxter	0.21
Remsen City Of STP	Remsen	0.2
Brooklyn City Of STP	Brooklyn	0.2
Corwith City Of STP	Corwith	0.2
Keota WWTP	Keota	0.2
Melcher-Dallas WWTP	Melcher-Dallas	0.2
Cincinnati City Of STP	Cincinnati	0.2
Leon WWTP	Leon	0.2
Jesup WWTP	Jesup	0.2
Edgewood WWTP	Edgewood	0.2
Lenox City Of STP	Lenox	0.2
Traer Municipal Water Plant	Traer	0.19
Cascade Municipal Utilities WWTP	Cascade	0.19
Villisca City Of STP	Villisca	0.18
Dike WWTP	Dike	0.18
Laurens City Of STP	Laurens	0.18
Kingsley City Of STP	Kingsley	0.18
Ossian City Of STP	Ossian	0.18
Walnut City Of STP	Walnut	0.17
Rockwell WWTP	Rockwell	0.17
Walford WWTP	Walford	0.17
Ely City Of STP	Ely	0.17

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Wastewater treatment in Iowa: 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 · Activated sludge · Oxidation ditch · 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 Iowa.” Updated October 26, 2026. https://klarifi.io/facilities/iowa

Need a custom cut of the data for a state, a county or a list of plants? Email info@klarifi.io.

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