Lagoon systems: wastewater treatment plants in Indiana
189 plants · 44% of the state · 124 MGD reported by 176 plants
Klarifi identifies 189 publicly owned wastewater treatment plants with lagoon systems in Indiana, 44% of the 432 plants in the state (124 MGD reported by 176 plants). The largest is Saniatry District Of Hammond in Hammond at 25.83 MGD.
Lagoon systems treat wastewater in large earthen ponds over weeks of retention time, with or without mechanical aeration. They serve thousands of small towns because they are cheap to run, but they struggle with ammonia and nutrient limits, fill with sludge over decades and are the plants most often converted or upgraded when a permit is renewed.
The largest lagoons in Indiana
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | Saniatry District Of Hammond | Hammond | 25.83 | IN0023060 | Apr 2027 | 21 |
| 2 | Lafayette WWTP | Lafayette | 15.2 | IN0032468 | Jul 2028 | 0 |
| 3 | East Chicago Sanitary District | East Chicago | 13.24 | IN0022829 | Jun 2026 | 44 |
| 4 | Dillman Waste Water Treatment Plant | Bloomington | 8.64 | IN0035718 | Aug 2029 | 7 |
| 5 | City Of Kokomo Waste Water Treatment Facility | Kokomo | 5.96 | IN0032875 | Nov 2026 | 19 |
| 6 | City Of La Porte - Wastewater Treatment Plant | La Porte | 3.47 | IN0025577 | Feb 2030 | 39 |
| 7 | Franklin Wwtp, City Of | Franklin | 3.07 | IN0021181 | Aug 2027 | 18 |
| 8 | Seymour Wastewater Treatment Facility | Seymour | 3.02 | IN0024473 | Apr 2031 | 22 |
| 9 | Peru Utilities WWTP | Peru | 2.92 | IN0032328 | Nov 2030 | 24 |
| 10 | New Castle WWTP | New Castle | 2.66 | IN0023914 | Jul 2031 | 37 |
| 11 | Washington WWTP | Washington | 2.46 | IN0025658 | Jun 2028 | 132 |
| 12 | Brownsburg WWTP | Brownsburg | 2.24 | IN0021245 | Sep 2030 | 8 |
| 13 | Frankfort Wwtp, City Of | Frankfort | 2.13 | IN0022934 | Apr 2030 | 7 |
| 14 | Plainfield North Water Pollution Control Facility | Plainfield | 1.77 | IN0021202 | Apr 2028 | 9 |
| 15 | Sellersburg WWTP Rehab & Expansion | Sellersburg | 1.4 | IN0020419 | Aug 2030 | 10 |
| 16 | Columbia City Water Department | Columbia City | 1.34 | IN0022624 | Dec 2027 | 46 |
| 17 | Bluffton Wastewater Treatment Facility | Bluffton | 1.14 | IN0022411 | Nov 2030 | 5 |
| 18 | Brazil WWTP | Brazil | 1.09 | IN0021211 | Apr 2030 | 11 |
| 19 | North Vernon WWTP | North Vernon | 1.05 | IN0020451 | Jan 2030 | 74 |
| 20 | Bargersville Municipal WWTP | Bargersville | 0.92 | IN0022314 | Apr 2027 | 16 |
| 21 | Alexandria WWTP | Alexandria | 0.92 | IN0020044 | Jul 2027 | 13 |
| 22 | Western Wayne Regional Sewer District WWTP | Cambridge City | 0.88 | IN0054402 | Sep 2028 | 3 |
| 23 | Portland WWTP | Portland | 0.88 | IN0020095 | May 2028 | 52 |
| 24 | Hartford City WWTP | Hartford City | 0.84 | IN0021628 | Aug 2029 | 67 |
| 25 | Sullivan WWTP | Sullivan | 0.83 | IN0024554 | Mar 2031 | 33 |
Contacts and project signals for every plant on this list
Klarifi adds verified decision-maker contacts, permit limits, discharge monitoring data and the capital projects planned in each city, filterable by technology, size and compliance record.
Other technologies in Indiana
Lagoon systems in other states
Lagoon systems in Indiana: 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.