A portion of Baltimore’s suburbs, including a shopping complex and business district near the region’s busy airport, has been put under a growth moratorium to control the threat of more wet-weather sewage overflows into the Patapsco River. The stoppage could potentially last for years.

Anne Arundel County’s public works department announced the immediate development cutoff February 26, saying that peak wastewater flows in the northwestern portion of the county have exceeded the capacity of the sewer network to handle them.

The affected area includes Linthicum Heights, Hanover and Pumphrey.

Wastewater from that area travels through a sewer line maintained by neighboring Baltimore County before being treated at the Patapsco Wastewater Treatment Plant in South Baltimore.

While the sewer lines can handle average daily wastewater flows, county officials said rainfall leaking into the aging, cracked pipes cause the peak flows to exceed limits set under an agreement Anne Arundel has with its neighboring jurisdictions.

Anne Arundel has been piping wastewater to the city from that area since 1939, and forging a pact in 1976 to share sewer and pumping station capacity with Baltimore and Howard counties.

When county officials spotted the problem in February, they tried without success to obtain a greater share of the regional sewer capacity. The city and county refused, citing their legal obligations under longstanding federal and state consent decrees to reduce wet-weather flows and eliminate chronic sewage overflows.

“Our multi-county team exhausted all options before arriving at the conclusion that we cannot approve any new connections in these specific areas,” said Karen Henry, director of the Anne Arundel County DPW. “Our primary focus is to protect the health of our residents and the environment by avoiding sanitary sewer overflows.”

[This story was first published in the Bay Journal on 3/6/26. It initially reported, per county officials, that Baltimore-Washington International Thurgood Marshall Airport was included in a map of the moratorium area. County officials have since said BWI is not affected.]

The Patapsco plant can treat no more than 73 million gallons of wastewater daily, and there are no plans to increase that capacity, according to Mary Stewart, city public works spokesperson.

The city “does not make decisions regarding local development opportunities,” she said, but provides neighboring jurisdictions with computer-modeling estimates of how much wastewater the plant can accept.

Sewage overflows have been a problem for decades in Baltimore and its suburbs, posing health risks for swimming or wading in local streams or the harbor, especially after rainstorms.

The city has spent $930 million repairing and replacing leaky sewer lines since agreeing to curb overflows in 2002. It reports reducing wet-weather sewage releases by 84%, but recently asked regulators for a 16-year extension until 2046 to eliminate them.

County Sewage Overflows

Northwestern Anne Arundel experienced two recent sewage overflows of its own. The county health department closed portions of the lower Patapsco to wading or swimming for nearly a week each in early January and mid-February after two pumping station breakdowns released sewage into the water.

The moratorium affects a relatively small part of Anne Arundel, and the 9,000 residents and businesses currently connected to the sewer there should not be affected, according to public works spokesperson Amy Mininger.

But new sewer connections would be put on hold in neighborhoods and commercial properties on three sides of Baltimore-Washington International Thurgood Marshall Airport, a regional travel and business hub that supports more than 100,000 jobs, according to BWI.

Included in the affected area are Arundel Mills mall and the BWI Business District. Though the airport’s wastewater also is piped through the combined interceptor to the Patapsco treatment plant, Mininger said it is not affected. The airport was granted its own separate sewerage allocation decades ago under the multi-county agreement, Mininger explained.

She said officials don’t have an estimate of how many new homes or businesses are on hold because of the moratorium. County officials have identified 18 projects in the development pipeline, she said, that will have to wait to hookup to the sewer system. Any projects that have already received approval may proceed.

To relieve the capacity crunch, the county is looking at diverting wastewater flows from the Patapsco plant to the Patuxent River or Cox Creek facilities, or to both. But that diversion could take at least five years to complete, according to a county notice.

In the meantime, said the public works spokesperson, county officials intend to see if the airport has any unused wastewater flow that it might be willing to provide to ease the moratorium.