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Storm Drain Outfall Monitoring

Imagine yourself walking beside a small stream, in a park, or near your house. You are admiring the ripple of the water as it flows over the pebbly bottom and enjoying the shady trees that line the banks. Then you notice a large pipe, about 36 inches in diameter, protruding from the bank. That is a stormwater outfall. You notice a strange smell and that the water flowing from the pipe is discolored. You call Baltimore County to express your concerns.

Citizens exploring their neighborhoods or walking by these outfalls are the County’s best resource to insure that the outfalls are free of pollutants. Baltimore County has a program to monitor (PDF) the flow from the 3,509 outfalls in the County. However, the random inspections rarely result in identifying a problem because of the intermittent nature of pollutant flows from outfalls. Citizen calls and observations are the most effective way to identify problems with the storm drain system. Prompt response from the County leads to detecting and eliminating pollutants entering our streams.

Stormwater Runoff

All around Baltimore County, a system of pipes transport water from rainstorms away from streets, parking lots, rooftops and parking garages and channels that water into neighborhood streams, or a river, or other waterbody. The site where the water flows from the pipe and into the waterbody is called the outfall.

The stormwater that flows into the streams is considered discharge by the federal government and requires Baltimore County to obtain a permit through the National Pollutant Discharge Elimination System (NPDES). The permit requires the County to monitor the outfalls to detect and eliminate any pollutants entering the streams. Baltimore County Department of Environmental Protection and Sustainability (EPS) conducts the monitoring of the outfalls and screens more than 200 outfalls annually. However, every year it receives 10,000 calls from citizens that help it target inspections, and locate and eliminate pollution.

Pollutants can enter the stormdrain system in numerous ways. Sometimes a citizen or company has illegally dumped oil, automotive fluids, or other substances in or near a storm drain. Municipal sewer lines might be leaking, blocked, or overflow. A private septic system might have failed and leaked effluent into a nearby storm drain. Other times a pipe is illegally connected to the storm drain system. The pollutants resulting from these sources are often intermittent and not present or detectable during inspection. This is why citizen calls have been an effective tool in helping to protect our local waterways from pollution. You can report an environmental concern.

Monitoring Discharges

You and Baltimore County are important partners in the storm drain monitoring program. If you would like to find out about other ways EPS is monitoring our water resources and protecting our streams, view the monitoring overview page. Opportunities to help monitor streams are also available through your local watershed association.

In addition to stormwater outfall monitoring, Baltimore County conducts chemical monitoring, biological surveys and evaluation of the physical condition of streams. Together, the data helps identify the streams that are at risk and contributes to creating an informed plan to reduce pollutants and improve water quality.  Results of EPS's monitoring are found in the annual NPDES report.

Contact Information
Watershed Management and Monitoring
Phone: 410-887-5683
Fax: 410-887-4804

Revised July 24, 2015

Revised April 6, 2016         


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