Clean Water Act Violations: How NPDES Permits Work
The Clean Water Act\'s National Pollutant Discharge Elimination System (NPDES) is the primary mechanism for controlling industrial water pollution in the United States. Any facility that discharges pollutants into navigable waters must obtain an NPDES permit specifying what it can discharge, at what concentrations, and under what monitoring requirements. Violations of NPDES permits are tracked in EPA ECHO and appear in EmissionsLookup facility profiles.
How NPDES Permits Are Structured
An NPDES permit is a facility-specific legal document that sets effluent limitations — the maximum concentration or load of specific pollutants the facility may discharge. These limitations are technology-based (reflecting what pollution control is achievable with available technology) or water-quality-based (set to protect the receiving water body\'s designated uses). A facility discharging into a high-quality trout stream will face more stringent limits than one discharging into a lower-quality industrial waterway.
Discharge Monitoring Reports
NPDES-permitted facilities must submit Discharge Monitoring Reports (DMRs) — typically monthly — reporting their actual discharge concentrations against permitted limits. DMRs are self-reported and flow into EPA\'s ICIS-NPDES database, which feeds ECHO. When a facility reports discharges that exceed permit limits, these appear as CWA violations in ECHO. Because violations are self-reported through DMRs, they\'re relatively comprehensive for NPDES — which is why some facilities show more CWA quarters of noncompliance than CAA violations (where violations may only be detected during inspections).
Stormwater NPDES
Industrial stormwater — precipitation that runs off industrial sites, picking up pollutants — is also regulated under NPDES. Facilities in most industrial sectors must obtain a stormwater permit and implement a Stormwater Pollution Prevention Plan (SWPPP). Stormwater violations are less frequently captured in ECHO than process discharge violations, partly because stormwater is episodic and harder to monitor continuously.
Using ECHO Water Compliance Data
On EmissionsLookup, the water compliance column on facility profiles shows CWA quarters of noncompliance. A facility with high water noncompliance but clean air and hazardous waste records has a specific compliance problem with its water discharges. Browse facilities with water violations using the filters at the violations page. For context on water quality in specific regions, CensusDepth includes some water-related environmental indicators from the ACS.