MS4 Permits
Municipal Separate Storm Sewer System Permit Requirements
The Clean Water Act (CWA) prohibits discharge from a point source. There are 3 major point source types (publicly owned treatment works (POTWs), industrial facilities, and discharges associated with urban runoff) that are routinely permitted and monitored to allow these discharges. In addition to the National Pollution Discharge Elimination System (NPDES), Municipal Separate Storm Sewer Systems (MS4) permits regulate point source discharges from urban runoff systems to help reduce contamination and improve our waterways. AQUALIS understands and adheres to both federal and state regulations to ensure your system is compliant. While each state varies in requirements, we have experience completing the general requirements applicable to all MS4 permits. We also provide the long-term maintenance, monitoring, and inspections that are required to maintain the permit and to verify BMPs are working effectively.
Permit Regulations
Municipal Separate Storm Sewer Systems (MS4) permits allow discharge from public stormwater systems in bodies of water. Permits are issued by the State, and many States expand to regulate stormwater otherwise left unregulated and can impose laws that vary from the CWA requirements. If drainage or discharging to a water body with Total Maximum Daily Load (TMDL) requirements, the AQUALIS staff will review with the municipality the additional measures that can be taken toward gaining compliance with the TMDL through the MS4 permit.
MS4 Phases
Municipal stormwater permits have two different phases to regulate runoff from MS4 systems. Phase I permits regulate the runoff from large and medium MS4s that are owned by Communities or State. Phase II permits regulate discharge from smaller population MS4s, and to specifically include unincorporated urban areas. Both permit phases require the development and implementation of a Stormwater Management Program (SWMP) that includes the 6 Minimum Control Measures (MCMs).
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Permit Requirements for All MS4s include:
- That the discharged water quality meets applicable standards
- Having best management practices (BMPs) implemented to reduce discharge pollutants
- Reduce pollutant discharge to the “maximum extent practicable” or MEP Standard
- Stormwater Management Program (SWMP) and/or Stormwater Pollution Prevention Plan (SWPPP)
- Map of MS4, including jurisdictional boundaries, MS4 outfalls and receiving waters
- Annual reports with summary data of maintenance actions, proposed revisions, and program status
Additional Permit Requirements for Phase I MS4s
Phase I MS4 permits have more requirements, as they represent larger populations. These requirements include:
- Structural and source control measures
- Include BMPs that reduce stormwater runoff onto local streets, roads, and highways
- Oversight and inventory management of industrial facilities
- Flood management evaluation to assess impact of flooding and water quality
- Good Housekeeping measures to address pesticides, herbicides, and fertilizer contamination
- Develop emergency program to respond to spills discharging from the MS4
- Financial analysis
- Public information and educational programs
- Monitoring or BMPS, TMDL success, and gathering stormwater data
County and Department of Transportation Implement GSI
“Working with the EPA, municipalities and local firms including AQUALIS’s Engineering Division, RPWIN has been able to improve water quality, reduce runoff and pollutant loads, slow the velocity of water volume, restore natural habitats and improve outdoor recreational opportunities.”
Did you receive an NOV? Have an urgent need? We can help.
Notices of Violation (NOVs) or Corrective Notices should be taken seriously. Contact AQUALIS today to learn how to resolve the issue and comply with regulations.