Stormwater Pollution

Street drain, stormwater runoff. Photo credit: Abramov Timur / Shutterstock

What is a watershed?

A watershed is an area of land that drains to a particular river, lake, bay, or other body of water. We all live in a watershed: some are large like the Chesapeake Bay, while others are small like your local stream or valley.

The Chesapeake Bay watershed stretches more than 64,000 square miles, and covers parts of Maryland, DC, Virginia, Delaware, Pennsylvania, New York, and West Virginia. Within the watershed, there are more than 100,000 streams and rivers called tributaries or subwatersheds that eventually flow into the Bay.

Baltimore City is covered by 4 major sub-watersheds: the Gwynns Falls, the Jones Falls, the Herring Run, and the Northern Branch of the Patapsco River (Harbor).

Clean Water Action works in the Chesapeake Bay watershed maintaining the health of both watersheds and subwatersheds, including the Anacostia River, the Patuxent River, and the Patapsco River.

The health of watersheds, the people living in them, and the water are all connected.

What is stormwater?

Stormwater is the polluted runoff gathered from rain, severe thunderstorms, and even snow from roads, parking lots, and other impervious surfaces, where runoff collects pollutants and carries them downstream, ultimately into the Chesapeake Bay. It is the only major source of water pollution that is increasing in Maryland.

Urban watersheds, like those found in Maryland, DC, and Virginia, require rigorous polluted runoff management programs because they have:

  • More people (more garbage & cars)
  • More pavement (fewer green space to filter pollutants)
  • More problems (flooding, dumping, neglected infrastructure/pipes, pollution)

Under the streets of Baltimore there are three separate systems of pipes: one for drinking water, one for sewage, and one for rainwater.

When it rains, stormwater picks up whatever is in the street: trash, oil, waste, fertilizers, pesticides, chemicals, pet waste, and sediment.

That polluted runoff flows across the street, down storm drain inlets, through stormwater pipes, to places where the pipes empty directly - without filtration or cleaning - in the rivers, harbors, and Chesapeake Bay. In Baltimore, there are more than 350 of these outfalls in the harbor and Chesapeake Bay.

Polluted runoff makes our waterways unsafe for swimming, threatens seafood, and causes localized flooding and property damage. These pollutants then contaminate not only our watersheds, but also our drinking water sources. Polluted runoff causes beach closures and water contact and seafood consumption advisories. In fact, scientists are now discovering intersex fish as a result of the chemicals in the increased polluted runoff into local waterways.

Cleaning up our waterways as a result of this stormwater runoff can be a huge financial burden. In Prince George’s County, it costs $3 million a year for litter cleanup. To clean the Anacostia River, sedimentation must be used, which costs $100-$500 million.

Examples of successful mitigation projects

In Baltimore County, a stream restoration project in the White Marsh Run Watershed addressed the bed and bank erosion issue within the watershed, which reduced the amount of stormwater runoff.

In Prince George’s County, a 30-year contract with Corvias Solutions was signed to manage the county’s stormwater program. This project allows the county and Corvias Solutions to retrofit 4,000 acres of impervious surface in the county

In the Chesapeake Bay, there has been a decrease in both nitrogen and phosphorus pollution due to recent stormwater pollution controls. Between 2009 and 2015, nitrogen loads decreased by about eight percent; and phosphorus loads decreased from by about twenty percent. Continued stormwater remediation efforts aim to further reduce the nutrients entering the Chesapeake Bay, since nutrient pollution is one of the largest contributors to the Bay’s poor health.


Stormwater remediation efforts have been mandated at both the federal and state levels. Maryland is now required by the EPA to treat 20% of its untreated impervious surfaces for stormwater runoff by 2019.

To meet this goal, in 2012, the state of Maryland mandated that a stormwater fee be enacted in the following ten jurisdictions: Anne Arundel, Baltimore, Carroll, Charles, Frederick, Harford, Howard, Montgomery, and Prince George’s Counties and Baltimore City.

Intended to fund stormwater remediation projects, the stormwater fee is a service fee that charges residential, commercial, and private properties based on the amount of impervious surface on their property.

However, in 2015, this mandate for a stormwater fee was lifted - but not the need to complete the projects the fee was designed to fund. Those counties and cities now are permitted to eliminate or phase out the fee, provided that they submit a Financial Assurance Plan (FAP) to the Maryland Department of the Environment (MDE).

The Financial Assurance Plan should detail the current and projected costs of stormwater remediation projects, as well as the sources of funding for these projects. These remediation projects are necessary because the jurisdictions will still be held to the federal and state mandate of treating 20% of untreated impervious surfaces.

Some jurisdictions, such as Harford County, have repealed the stormwater fee. Others, such as Howard County and Baltimore City, have rejected measures to phase out the fee. However, Harford, Howard, Frederick and Carroll counties are attempting to appeal the requirements of the MDE’s MS4.

The deadline to repeal or reduce the stormwater fee and submit a Financial Assurance Plan is July 1, 2016. Ninety days after the submittal, MDE will decide whether the FAP shows sufficient funding for at least 75% of the impervious surface area restoration cost.

What can you do?

The programs introduced will improve the quality of life in communities across Maryland and will also benefit state tourism, seafood, and recreation industries, as well as provide thousands of job opportunities.

  • There are several simple solutions that can decrease stormwater runoff, and for residents of Baltimore City, your stormwater fees:
  • Install a rain barrel. Rain barrels reduce flooding in yards and basements, reduce water and sewage bills, and will absorb slowly into the ground which replenishes the groundwater supplies and increases water resources.
  • Create a rain garden. Use low areas in your yard to plant native vegetation, which allows water to infiltrate naturally into the ground rather than run off into the storm drainage.
  • Participate in river and stream cleanups. These occur statewide, and Clean Water Action organizes cleanups each season with communities across the sub-watersheds.
  • Go organic. Planting organic and native plants can help increase our pollinator population and provide fresh food for families, all while reducing polluted runoff to the local waterways.
  • Attend local hearings. Each of the ten jurisdictions that must submit a Financial Assurance Plan is also required to hold a public hearing to discuss the plan. Staying informed about what your jurisdiction is doing can help you learn more about how you can reduce stormwater runoff.