Municipal Separate Storm Sewer System (MS4) Discharge Permit

Discharges from municipal separate storm sewer systems (MS4s) are regulated under the Virginia Stormwater Management Act, the Virginia Stormwater Management Program (VSMP) Permit regulations, and the Clean Water Act as point source discharges. The permits are administered and issued by the Virginia Department of Environmental Quality. 

MS4 regulations were developed and implemented in two phases. Implementation of the first phase began in the early 1990s and required that operators of MS4s serving populations of greater than 100,000 people (per the 1990 decennial census) apply for and obtain a permit to discharge stormwater from their outfalls. Currently 11 localities in Virginia are phase I MS4s, including the Cities of Norfolk, Virginia Beach, Portsmouth, Chesapeake, Newport News and Hampton. 

The second phase of MS4 regulations became effective March 23, 2003 and required that operators of small MS4s in "urbanized areas" (as defined by the latest decennial census) obtain a permit to discharge stormwater from their outfalls. Stormwater discharges from Phase II (small) MS4s are regulated under the General Permit for the Discharge of Stormwater from Small Municipal Separate Storm Sewer Systems.  Small MS4s include 90 different storm sewer systems operated by cities, counties, towns, federal facilities such as military bases, Veteran's Affairs hospitals and research facilities, Department of Defense facilities and parkways, and state facilities such as community colleges and public universities. The remaining cities in Hampton Roads as well as the more populous counties, including York and James City, are Phase II MS4 communities. In addition, the College of William and Mary and all the local military installations operate MS4 facilities under separate permits. Current MS4 permittees are listed on DEQ's website. 

The City of Williamsburg has operated a MS4 program since first registering in July 1, 2003. The program is administered by the Department of Public Works.  Under the general permit, small MS4s must develop, implement, and enforce a program that includes the following "six minimum control measures":

  • Public education and outreach on stormwater impacts
  • Public involvement and participation 
  • Illicit discharge detection and elimination 
  • Construction site stormwater runoff control
  • Post-construction stormwater management in new development and redevelopment
  • Pollution prevention/good housekeeping for municipal operations

MS4 programs must be designed and implemented to control the discharge of pollutants from their storm sewer system to the maximum extent practicable in a manner that protects the water quality in nearby streams, rivers, wetlands and bays.

The City of Williamsburg renewed the MS4 permit in April 2018 for a fourth 5-year cycle through June 30, 2023.  The 2013 and 2018 MS4 General Permits also included a special condition to address impaired waters with a Total Maximum Daily Load (TMDL) including the Chesapeake Bay TMDL. Below are links to the 2018-2023 MS4 Permit Package, our current program plan, as well as the annual reports for previous year's activity. Prior year annual reports are available for review in the Department of Public Works office and or online at the links on the left menu. 

FY22  Annual Report

FY18-2023 City of Williamsburg MS4 Program Plan

MS4 General Permit Package 2018

The public is invited to provide comments on the MS4 Program plan. Please submit all written comments to the Department of Public Works office or via e-mail to