Sanitary Sewer Overflow Enforcement Initiative


On March 28, 2005, a new regulation (COMAR 26.08.10, Overflows and Bypasses) that addresses reporting and public notification about sewage overflows and bypasses became effective. The Maryland Department of the Environment (“Department” or “MDE”) has been tracking reports of overflows by owners and operators of sewage systems in the State. MDE is concerned that there are still a significant number of overflows that occur across the State. These sewage overflows adversely impact State waters and pose a risk to public health from raw or partially treated sewage containing elevated levels of bacteria and disease causing pathogens. 

Enforcement Initiative

The Department implemented an enforcement initiative effective January 1, 2009 as a further step in its efforts to address unauthorized discharges of pollutants resulting from sanitary sewer overflows. The Department has taken numerous enforcement actions independently and jointly with the Environmental Protection Agency (EPA) and citizen groups over the last ten years that included orders for system upgrades and penalties for unlawful discharges. These actions are intended to focus greater attention on illicit discharges and to encourage municipalities and private sewer system owners to do all they can to identify and correct problems in their systems to prevent overflows. In the past, MDE targeted those systems with numerous sewage overflows or large volume overflows for enforcement actions.

Penalties and Orders

Under the enforcement initiative, MDE has begun to assess penalties for all sewage overflows, with the exception of permitted combined sewer overflows, unless the owner or operator of the system can clearly demonstrate that the overflow was beyond their control and in spite of taking all reasonable steps to properly operate, maintain and improve sewer system infrastructure. Under State and federal law, penalties for sewage overflows can range from $1,000 to $32,500 per day respectively for each overflow. The Department may also issue orders requiring improvements to prevent and eliminate sewer overflows from systems with repeated overflows from the same pump station, manhole or sewer line, large volume overflows or overflows that are due to poor system maintenance, operation or design.

Responsibility of Sanitary Sewer Operators

Operators of sanitary sewers are reminded of their responsibility to take all appropriate steps to report all overflows, maintain records of sewage overflows and backups as provided by COMAR 26.08.10 and to operate and maintain your sewer systems and wastewater treatment plants in good condition to prevent sewage overflows and unlawful discharges to waters of the State. Failure to eliminate or report overflows will result in enforcement action by MDE through the issuance of orders and/or penalty assessments.

Click here​ to view MDE letter sent to operators of sanitary sewers.

Contact Information

The Maryland Reported Sewer Overflow Database contains bypasses, combined sewer overflows (CSOs) and sanitary sewer overflows (SSOs) reported to the Maryland Department of the Environment (MDE) from January 2005 through the most recent update. MDE updates this database regularly. Although MDE requires that all public sewer system owners or operators report overflows to us, there may be incidents that were not reported. Note that overflow amounts provided by the person reporting the overflow may be estimated using best professional judgment or they may be actual readings from flow measurement devices when available.

The most up to date information is available through Maryland’s Open Data Portal at​  The search form below does not have data after January 2022. We are working to provide search functionality using the Open Data Portal.

If you have any questions about this database, please contact Andrew Gosden, Program Manager at 410-537-3510.

Human Trafficking GET HELP

National Human Trafficking Hotline - 24/7 Confidential

1-888-373-7888 233733 More Information on human trafficking in Maryland

Customer Service Promise

The State of Maryland pledges to provide constituents, businesses, customers, and stakeholders with friendly and courteous, timely and responsive, accurate and consistent, accessible and convenient, and truthful and transparent services.

Take Our Survey

Help Stop Fraud in State Government

The Maryland General Assembly’s Office of Legislative Audits operates a toll-free fraud hotline to receive allegations of fraud and/or abuse of State government resources. Information reported to the hotline in the past has helped to eliminate certain fraudulent activities and protect State resources.

More Information