Iowa wastewater permits expiring in 2026
71 NPDES permits · 0 MGD combined average flow
71 publicly owned wastewater treatment plants in Iowa hold NPDES permits that expire during 2026, issued by Iowa Department of Natural Resources. The table lists each plant with its permit number, expiry month, average flow, treatment technology and three-year violation count, in order of expiry.
An NPDES permit runs for five years. To keep discharging, a plant must apply for renewal at least 180 days before the expiry date, and the renewed permit usually arrives with tighter effluent limits, new monitoring requirements or a compliance schedule. That is why the year a permit expires is the year a plant starts budgeting for upgrades: nutrient removal, disinfection, capacity or controls.
| Facility | City | Avg flow (MGD) | NPDES permit | Expires | Technology | Violations (3y) |
|---|---|---|---|---|---|---|
| Cherokee WWTP | Cherokee | — | IA0059005 | Jan 2026 | Clarifiers, Uncovered lagoons, Biogas balloons | 81 |
| Coralville WWTP | Coralville | — | IA0020788 | Mar 2026 | Clarifiers, Carrousels / oxidation ditches | 1 |
| Oskaloosa NE WWTP | Oskaloosa | — | IA0038539 | Mar 2026 | Clarifiers, Uncovered lagoons, Biogas balloons | 49 |
| Oskaloosa SW STP | Oskaloosa | — | IA0038521 | Mar 2026 | Clarifiers, Uncovered lagoons, Biogas silos, Biogas balloons | 5 |
| Albia City Of STP (north) | Albia | — | IA0036871 | Apr 2026 | Aerated lagoons, Uncovered lagoons | 62 |
| Ida Grove WWTP | Ida Grove | — | IA0020761 | Apr 2026 | Clarifiers | 12 |
| Kanawha City Of STP | Kanawha | — | IA0026000 | Apr 2026 | Uncovered lagoons | 8 |
| Fairfield City Of STP | Fairfield | — | IA0035076 | May 2026 | Uncovered lagoons, Biogas silos, Biogas balloons | 28 |
| Oelwein WWTP | Oelwein | — | IA0032344 | May 2026 | Uncovered lagoons | 16 |
| Sac City WWTP | Sac City | — | IA0033090 | May 2026 | Uncovered lagoons, Biogas silos, Biogas balloons | 11 |
| Mitchell County WW Pretreatment Plant | Osage | 0.03 | MO0030821 | Jun 2026 | Carrousels / oxidation ditches, Biogas silos | 111 |
| Clarence WWTP | Clarence | — | IA0027201 | Jun 2026 | Uncovered lagoons | 2 |
| Corydon City Of STP | Corydon | — | IA0049573 | Jun 2026 | Aerated lagoons, Uncovered lagoons | 46 |
| Cresco WWTP | Cresco | — | IA0021334 | Jun 2026 | Clarifiers | 12 |
| Davenport Wastewater Treatment Plant | Davenport | — | IA0043052 | Jun 2026 | Clarifiers, Biogas silos, Biogas balloons | 0 |
| Deep River, City Of STP | Deep River | — | IA0071943 | Jun 2026 | Uncovered lagoons | 1 |
| Galva WWTP | Galva | — | IA0056537 | Jun 2026 | Covered lagoons | 57 |
| Manchester WWTP | Manchester | — | IA0021032 | Jun 2026 | Uncovered lagoons, Biogas silos, Biogas balloons | 1 |
| Marengo City Of STP | Marengo | — | IA0047937 | Jun 2026 | Aerated lagoons, Uncovered lagoons | 96 |
| Minden City Of STP | Minden | — | IA0048330 | Jun 2026 | Uncovered lagoons | 7 |
| Rock Rapids City Of STP | Rock Rapids | — | IA0032786 | Jun 2026 | Clarifiers, Uncovered lagoons, Biogas balloons | 2 |
| Aurelia WWTP | Aurelia | — | IA0028908 | Jul 2026 | Uncovered lagoons | 1 |
| Brayton City Of STP | Brayton | — | IA0057100 | Jul 2026 | Uncovered lagoons | 1 |
| Earling City Of STP | Earling | — | IA0025364 | Jul 2026 | Covered lagoons | 29 |
| West Point City Of STP | West Point | — | IA0043109 | Jul 2026 | Aerated lagoons, Uncovered lagoons | 1 |
| Allerton City Of STP North | Allerton | — | IA0054054 | Aug 2026 | Uncovered lagoons | 6 |
| Allerton City Of STP South | Allerton | — | IA0054046 | Aug 2026 | Aerated lagoons, Uncovered lagoons | 34 |
| Clermont WWTP | Clermont | — | IA0024465 | Aug 2026 | Aerated lagoons, Uncovered lagoons | 29 |
| Elk Horn City Of STP | Elk Horn | — | IA0027677 | Aug 2026 | Uncovered lagoons | 7 |
| Iowa Great Lakes Sanitary District WWTP | Milford | — | IA0059765 | Aug 2026 | Clarifiers, Biogas silos | 15 |
| Laurens City Of STP | Laurens | — | IA0025950 | Aug 2026 | Uncovered lagoons | 15 |
| Petersburg, City Of STP (eiruss) | Dyersville | — | IA0079740 | Aug 2026 | Uncovered lagoons | 2 |
| Tracy City Of STP (mahaska Rural Water Systems, Inc.) | Tracy | — | IA0081647 | Aug 2026 | Uncovered lagoons | 0 |
| Belmond City Of STP | Belmond | — | IA0041777 | Sep 2026 | Clarifiers, Biogas silos | 43 |
| Correctionville City Of STP | Correctionville | — | IA0023531 | Sep 2026 | Uncovered lagoons | 4 |
| Dallas Center City Of STP | Dallas Center | — | IA0035319 | Sep 2026 | Aerated lagoons, Uncovered lagoons | 25 |
| Goose Lake City Of STP | Goose Lake | — | IA0056944 | Sep 2026 | Uncovered lagoons | 23 |
| Martensdale City Of STP | Martensdale | — | IA0031836 | Sep 2026 | Uncovered lagoons | 1 |
| Martinsburg WWTP | Martinsburg | — | IA0078727 | Sep 2026 | Uncovered lagoons | 0 |
| Vail City Of STP | Vail | — | IA0032654 | Sep 2026 | Uncovered lagoons | 1 |
| Washington City Of STP | Washington | — | IA0032433 | Sep 2026 | Uncovered lagoons | 6 |
| Webster City WWTP | Webster City | — | IA0036625 | Sep 2026 | Clarifiers, Biogas silos, Biogas balloons | 12 |
| Auburn City Of STP | Auburn | — | IA0057029 | Oct 2026 | Uncovered lagoons | 1 |
| Blockton City Of (southern Ia Rural Water Assn.) | Blockton | — | IA0076023 | Oct 2026 | Uncovered lagoons | 0 |
| Brandon WWTP | Brandon | — | IA0028185 | Oct 2026 | Aerated lagoons, Uncovered lagoons | 32 |
| Granger WWTP | Granger | — | IA0041912 | Oct 2026 | Uncovered lagoons | 70 |
| Gravity, City Of-(southern Iowa Rural Water Association) | Gravity | — | IA0075957 | Oct 2026 | Uncovered lagoons | 0 |
| Middletown WWTP | Middletown | — | IA0025381 | Oct 2026 | Aerated lagoons | 10 |
| New London WWTP | New London | — | IA0025941 | Oct 2026 | Aerated lagoons | 2 |
| Stacyville, City Of STP | Stacyville | — | IA0035254 | Oct 2026 | Uncovered lagoons | 0 |
| Westside City Of STP | Westside | — | IA0040274 | Oct 2026 | Uncovered lagoons | 1 |
| Wyoming WWTP | Wyoming | — | IA0032646 | Oct 2026 | Aerated lagoons, Uncovered lagoons | 20 |
| Exira City Of STP | Exira | — | IA0027987 | Nov 2026 | Uncovered lagoons | 2 |
| Fairbank WWTP | Fairbank | — | IA0035041 | Nov 2026 | Aerated lagoons, Uncovered lagoons | 4 |
| Hartford City Of STP | Hartford | — | IA0066761 | Nov 2026 | Aerated lagoons, Uncovered lagoons | 30 |
| Lorimor City Of STP | Lorimor | — | IA0062910 | Nov 2026 | Uncovered lagoons | 0 |
| Rickardsville WWTP | Durango | — | IA0066311 | Nov 2026 | Uncovered lagoons | 0 |
| Ute City Of STP | Ute | — | IA0043010 | Nov 2026 | Uncovered lagoons | 6 |
| Vincent City Of STP | Vincent | — | IA0032930 | Nov 2026 | Uncovered lagoons | 13 |
| Carson City Of STP | Carson | — | IA0042901 | Dec 2026 | Clarifiers, Biogas balloons | 13 |
| Everly WWTP | Everly | — | IA0028916 | Dec 2026 | Aerated lagoons, Uncovered lagoons | 7 |
| Lanesboro City Of STP | Lanesboro | — | IA0062162 | Dec 2026 | Uncovered lagoons | 2 |
| Menlo WWTP | Menlo | — | IA0071374 | Dec 2026 | Uncovered lagoons | 2 |
| Minburn City Of STP | Minburn | — | IA0023418 | Dec 2026 | Uncovered lagoons | 4 |
| Mount Sterling, City Of STP | Mount Sterling | — | IA0076651 | Dec 2026 | Uncovered lagoons | 0 |
| Oxford Junction WWTP | Oxford Junction | — | IA0032450 | Dec 2026 | Aerated lagoons, Uncovered lagoons | 1 |
| Schleswig City Of STP | Schleswig | — | IA0036170 | Dec 2026 | Uncovered lagoons | 0 |
| Templeton WWTP | Templeton | — | IA0033782 | Dec 2026 | Uncovered lagoons | 4 |
| Thor City Of STP | Thor | — | IA0058581 | Dec 2026 | Uncovered lagoons | 0 |
| Webster WWTP | Webster | — | IA0078719 | Dec 2026 | Uncovered lagoons | 1 |
| West Chester City Of STP | West Chester | — | IA0072460 | Dec 2026 | Uncovered lagoons | 6 |
Iowa permit renewals in 2026: 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.