Anne Arundel County Halts Development After Patapsco Sewage Plant Reaches Capacity

Northwestern Anne Arundel County is closed to new development, a consequence of the 85-year-old Patapsco Wastewater Treatment Plant in South Baltimore hitting the ceiling on how much sewage it can accept from neighboring jurisdictions. The county's Department of Public Works announced the immediate moratorium on February 26, halting new subdivisions, building permits, and tenant fit-out approvals in Linthicum Heights, Hanover, and Pumphrey — a corridor that includes BWI Thurgood Marshall Airport and Arundel Mills shopping mall.

"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 Department of Public Works. "Our primary focus is to protect the health of our residents and the environment by avoiding sanitary sewer overflows."

The stoppage could potentially last for years, according to Bay Journal reporting. The county's formal press release, issued March 2, states the moratorium is effective immediately but sets no end date.

The decision followed two sewage overflows that shut down portions of the lower Patapsco River to wading and swimming for nearly a week each. A pumping station breakdown in early January released sewage into the water, prompting the county health department to post closures. A second breakdown struck in mid-February and produced the same result. Both incidents underscore what officials say is the core technical problem: aging, cracked sewer pipes that allow stormwater and groundwater to flood the system during wet weather — a process known as inflow and infiltration, or I&I — pushing peak wastewater flows above limits set under a multi-jurisdictional agreement, even when average daily flows remain within allowable caps.

Wastewater from the affected communities travels through the Baltimore County Patapsco Interceptor and Sewage Pumping Station before reaching the Patapsco plant, a 69-acre facility along the Patapsco River that has been treating sewage since 1940. Baltimore City public works spokesperson Mary Stewart told the Bay Journal the plant can treat no more than 73 million gallons per day and that there are no plans to increase that capacity. Stewart added that city officials "do not make decisions regarding local development opportunities" but provide neighboring jurisdictions with computer-modeling estimates of how much wastewater the plant can accept.

Anne Arundel has been routing wastewater from that area to Baltimore City since 1939, formalizing the arrangement through a 1976 pact that established shared sewer and pumping station capacity with Baltimore and Howard counties. That agreement now defines the peak-flow limits the county has exceeded. Baltimore City and Baltimore County are both under ongoing consent decrees that prevent them from allocating additional capacity to Anne Arundel, which the county's own press release describes as creating "an immediate bottleneck for new development."

All currently allocated Equivalent Dwelling Units will be honored under the moratorium, and county public works spokesperson Amy Mininger said the roughly 9,000 residents and businesses already connected to the sewer system in the affected area should not be affected. Exceptions to the permit freeze may be made for infill lots with failing septic systems, and most tenant fit-out permits will be evaluated individually, according to reporting by Patch.

The DPW characterized the geographic scope of the freeze as a relatively small portion of Anne Arundel County, but the presence of a major international airport and one of the region's largest shopping malls inside the moratorium boundary signals that the economic stakes extend well beyond the three residential communities named in the order.