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Community MS4 Program


Prince William County oversees a comprehensive program to control the stormwater pollutants that can wash directly into local waterways from the community's Municipal Separate Storm Sewer Systems (MS4). We operate under a very strict permit issued by the Virginia Department of Environmental Quality allowing the County to discharge into Waters of the United States. Under this permit, the Environmental Management team from Public Works must implement a collective series of programs aimed to reduce the discharge of pollutants from the local storm sewer systems (MS4) and thereby our local waterways to the greatest degree possible. Our goal is to protect the water quality of nearby streams, rivers, wetlands and bays.


  1. Prince William County MS4 Program Plan -- This is the County's current plan for controlling stormwater pollutants as required by DEQ. We welcome your questions and concerns. Please contact us at [email protected].
  2. See a problem, report a problem to [email protected] -- Please report issues you see including illicit discharge, illegal dumping, spills, runoff materials and pollution entering storm drains or streams, or other situations that could contaminate our waterways.
  3. Here is the link to the most recent Prince William County's annual report on our MS4 2023 Program. Please note: it takes several minutes to open this link due to the size of the report.
  4. Questions and Answers -- We will post public comments and questions as we receive them.
Public Works leads local efforts by taking the following actions:
  • Operate and maintain structural stormwater controls
  • Control discharge from areas of development and significant redevelopment
  • Control pollutants related to application of pesticides, herbicides and fertilizers
  • Implement an inspection program to enforce ordinances, which prohibit illicit connections and illegal dumping into the MS4
  • Screen the MS4 for illicit connections and illegal dumping
  • Implement standard investigative procedures to identify and terminate sources of illicit connections or discharges and maintain the County's storm sewer infrastructure
  • Prevent, contain and respond to spills that may discharge into the MS4
  • Limit the infiltration of sanitary seepage into the MS4
  • Identify, monitor and control discharges from municipal landfills; hazardous waste treatment, storage, disposal and recovery facilities; facilities subject to EPCRA Title III, Section 313; and any other industrial or commercial discharge the permittee determines to be contributing a substantial pollutant loading to the MS4
  • Generate long term plans to reduce pollutants and excess nutrients from entering the Chesapeake Bay
  • Control pollutants in construction site runoff
  • Conduct public education on stormwater

The Prince William County Service Authority identifies, monitors and controls discharges from municipal waste treatment, storage or disposal facilities. The Prince William County Department of Transportation works with the Virginia Department of Transportation to control issues on public streets, roads and highways through their own state permit. The towns of Dumfries and Occoquan, the Prince William County School System, City of Manassas and the City of Manassas Park also maintain their own MS4 permits separate from Prince William County.

Related MS4 Documents and past reports are available here. Please note: these files are large and will take several minutes to open. Thank you for your patience.