MS4 Stormwater Permit
The Virginia Department of Environmental Quality (DEQ) issues permits for the discharge of stormwater into waterways like Four Mile Run and the Potomac River. These permits, called municipal separate storm sewer system (MS4) permits, are good for five years. Arlington’s current MS4 permit (VPDES Permit No. VA 0088579) was issued on July 1, 2021.
Arlington was the first municipality in Virginia to receive an MS4 permit that included quantitative pollution reduction requirements to clean up the Chesapeake Bay in 2013. The Chesapeake Bay Total Maximum Daily Load (TMDL), which is commonly referred to as the “bay pollution diet,” requires significant reductions in nutrient and sediment pollution across the bay watershed. Local governments have 15 years to achieve the pollution reductions, over three MS4 permit cycles.
Each MS4 permit is good for five years, and Arlington's current permit will be in effect through mid-2026. During this permit cycle, Arlington is required to achieve a 35 percent reduction of its share of these bay TDML pollutants, in addition to the 5 percent reduction already achieved during Arlington's 2013-2018 permit. In the following permit cycle (2026-2031), Arlington will be required to reduce our final share of these Bay TDML pollutants (60 percent).
Supporting Programs
We began preparing for the permit and its more stringent requirements in 2008 with the adoption of the Stormwater Fund, which was converted to a stormwater utility fee in 2024. The stormwater utility fee provides funding for watershed management programs that help the County achieve the pollution reduction goals, such as:
Arlington Stormwater Pollution Prevention Plans (SWPPPs)
As part of the MS4 permit, Arlington works to prevent pollution on-site at County facilities. Each site or facility has a stormwater pollution prevention plan (SWPPP). The SWPPP includes best practices that keep pollutants safely contained and out of the storm drain network and streams. Only rain in the storm drain!