World wastewater treatment plant observatory · data as reported by each inventory
United States
EPA is the primary source in the 50 states and DC. HydroWASTE remains a non-additive alternative; HydroWASTE-only records retain their identity.
Choose an inventory. These are not comparable periods and have not been reconciled plant by plant.
Regulatory context
General reference. This is not an exhaustive review of applicable law.
United States: Clean Water Act / NPDES
NPDES regulates pollutant discharges from point sources to waters of the United States. The permit sets limits and monitoring conditions. A CWNS code identifies an inventory record, not an NPDES permit.
- Permit identifier and permitting authority: EPA or an authorized state.
- Outfall and receiving water; sewer connections follow a different control route.
- Current permit conditions, limits and dated measurements; these are not included in CWNS.
References reviewed: 2026-11-04. Individual applicability: undetermined. This profile does not establish authorization or compliance.
Territories: HydroWASTE source
HydroWASTE is the available primary source for Puerto Rico, Guam and the US Virgin Islands: reported or estimated population served. It is not added to EPA. The US regulatory reference does not establish applicability to an individual plant.