11 NPDES permits · 2 MGD combined average flow
11 publicly owned wastewater treatment plants in Maryland hold NPDES permits that expire during 2028, 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) |
|---|---|---|---|---|---|---|
| Rising Sun Town Of WWTP | Rising Sun | 0.2 | MD0020265 | Apr 2028 | Clarifiers, Uncovered lagoons, Carrousels / oxidation ditches | 22 |
| Pocomoke City Wastewater Treatment Facility | Pocomoke City | 0.52 | MD0022551 | May 2028 | Aerated lagoons, Covered lagoons, Uncovered lagoons, Carrousels / oxidation ditches | 0 |
| Union Bridge WWTP | Union Bridge | 0.12 | MD0022454 | May 2028 | — | 0 |
| Pinto/md Water Services WWTP | Pinto | 0.12 | MD0022748 | May 2028 | Aerated lagoons | 31 |
| Brunswick WWTP | Brunswick | — | MD0020958 | May 2028 | — | 0 |
| Twin Cities WWTP | Secretary | 0.13 | MD0055352 | Sep 2028 | Aerated lagoons | 58 |
| Flintstone WWTP | Flintstone | 0.01 | MD0055620 | Sep 2028 | — | 0 |
| Funkstown WWTP | Funkstown | — | MD0020362 | Sep 2028 | Uncovered lagoons | 0 |
| Wssc Damascus WRRF | Gaithersburg | 0.72 | MD0020982 | Dec 2028 | Clarifiers | 3 |
| Snow Hill WWTP | Snow Hill | 0.26 | MD0022764 | Dec 2028 | Clarifiers | 61 |
| Barton Business Park WWTP | Cumberland | 0.004 | MD0068896 | Dec 2028 | — | 0 |
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.