Stormwater Information

What is Stormwater?

As water from rain and snowmelt makes its way to the nearest stream or lake, it flows over rooftops, roads, parking lots, our backyards, and the entire land surface around us, it picks up pollutants such as trash, leaked oil and antifreeze, household fertilizers and pesticides, pet waste, sediment, and any other loose or leaking thing in our combined neighborhoods, and carries this slurry into the nearest stream. In many places in and around Manassas, there is a collection of drains, curbs, ditches, pipes and other structures placed to capture water that flows across roads, buildings, pavement, and other developed surfaces. This captured water is sent to a variety of stormwater ponds, basins, or other sites that were designed to remove some of these pollutants from the water before returning the water back to the natural stream. Stormwater therefore, is the combined treated and untreated water that runs across our communities before it reaches natural streams.

Stream

Stormwater Drains and Sewers are not the Same

The sanitary sewer is a system of underground pipes and tunnels that carry sewage from bathrooms, sinks and kitchens to a wastewater treatment plant where it is filtered, treated and discharged.

The stormwater drain only carries water runoff from snow and rain. It is not designed to carry sewage or accept hazardous wastes. Storm drain inlets are typically found in curbs and low-lying outdoor areas. It is not desirable to have stormwater sent to sanitary sewer treatment facilities, since it would be costly to treat stormwater as sewage and it may likely overwhelm the facility’s treatment capacity.

For Stormwater emergencies call the Operations Center (24/7) at 703-257-8353.

If you are experiencing a Police or Fire Emergency, dial 911.

Creek

Where does Stormwater Go?

The water runoff from a rainstorm or snowfall feeds our wetlands, rivers, lakes, reservoirs and groundwater. It's the same water that we use for recreation and sustains our local environment, including wildlife.

What is MS-4?

MS-4 is an abbreviation for Municipal Separate Storm Sewer System.

The “Municipal” part pertains to being in municipal or urbanized areas, as defined by the U.S. federal census bureau. Every ten years, the census bureau publishes the location of urbanized areas of the United States. The city of Manassas falls within one of these urbanized areas.

The four “S”s pertain to those urbanized area that have their sewer treatment systems separate from their stormwater infrastructure. There are separate regulations overseeing how sewer systems are maintained and operated, while the MS-4 permit regulates how these dedicated stormwater management systems are operated and maintained.

For additional information, please read our General Overview of MS-4.

MS-4 in the City of Manassas

  • There are 5,320 storm drains that connect to 23 public and approximately 34 private stormwater facilities in the city.
  • Surface water in the city flows into either Broad Run or Bull Run. Both of these watersheds drain into the Occoquan River, which in turn, empties into the Chesapeake Bay.

More things to consider

  • 80 percent of the Earth’s surface is covered by water.
  • Only 3 percent of the Earth’s water is fresh water.
  • Only 1 percent of the Earth’s water is suitable for drinking.
  • Each year 1.2 trillion gallons of untreated sewage, stormwater and industrial waste are dumped into U.S. waterways.
  • Stormwater feeds into our watershed and our supply of drinking water.
  • EVERYONE lives in a watershed.
  • Stormwater runoff is the nation's number one source of water pollution.
  • According to the American Petroleum Institute, an average of more than 239 million gallons of motor oil is used by car owners who change their own oil. An average of only 53 million gallons is recycled.
  • Decaying leaves and organic materials in the storm drain increase bacteria and mosquito production and decrease oxygen essential for fish life.
  • One gallon of oil in the storm drain can pollute up to one million gallons of stormwater.
  • The three largest sources of storm water pollution are: herbicides and pesticides from agriculture, urban runoff, and sediment from construction sites.
  • When lawn fertilizer enters the stormdrain, it can cause excessive algae growth and oxygen depletion.
  • The behavior of individuals contributes MORE to water pollution than business, industry and large public enterprise.
  • A typical city block generates more than 5 times more runoff than a wooded area of the same size.
  • It is estimated that 4 billion tons of sediment is eroded annually from construction sites into U.S. waterways.