12 NPDES permits · 2 MGD combined average flow
12 publicly owned wastewater treatment plants in Maryland hold NPDES permits that expire during 2026, issued by Maryland Department of the Environment. 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) |
|---|---|---|---|---|---|---|
| Northern Garrett High School | Accident | 0.005 | MD0024449 | Jan 2026 | — | 10 |
| Glen Arm Wastewater Treatment Plant (formerly Grumman Wwtp) | Glen Arm | — | MD0067903 | Jan 2026 | — | 22 |
| George'S Creek WWTP | Westernport | 0.77 | MD0060071 | May 2026 | Clarifiers, Aerated lagoons, Uncovered lagoons, Carrousels / oxidation ditches | 0 |
| Port Deposit WWTP | Port Deposit | 0.08 | MD0020796 | May 2026 | — | 39 |
| White Rock WWTP | Frederick | 0.01 | MD0025089 | May 2026 | — | 0 |
| Middletown WWTP | Middletown | 0.15 | MD0024406 | Jul 2026 | Aerated lagoons | 0 |
| Hebron WWTP | Hebron | 0.08 | MD0059617 | Jul 2026 | Aerated lagoons, Uncovered lagoons | 31 |
| Crestview Estates WWTP | Frederick | 0.01 | MD0022683 | Jul 2026 | — | 4 |
| New Germany State Park WWTP | Grantsville | 0.001 | MD0023981 | Jul 2026 | — | 0 |
| Chestertown WWTP | Chestertown | 0.63 | MD0020010 | Sep 2026 | Clarifiers, Uncovered lagoons | 5 |
| Sudlersville WWTP | Sudlersville | 0.09 | MD0020559 | Dec 2026 | Clarifiers, Aerated lagoons, Uncovered lagoons | 12 |
| Accident WWTP | Accident | 0.06 | MD0051721 | Dec 2026 | — | 46 |
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.