reduce phosphorus pollution by about 103 pounds a year and
nitrogen pollution by about 416 pounds a year—down from the
14,800 pounds of phosphorus and 108,000 pounds of nitrogen
annually discharged now.
Severn River, Maryland
The Severn River in Anne Arundel County, Maryland, dates
back as many as 10,000 years, based on geological findings.
But the current quality of its water can be traced largely to
the many subdivisions in its 81-square-mile watershed.
About one in three homes in Anne Arundel dispose of its
waste through a septic system rather than public sewer. Along
the Severn River alone are about 12,000 homes and businesses
on septic systems. Many of the systems were installed before
anyone understood the harm they can cause local water.
Backyard septics do little to remove nitrogen from human and
household waste. Much of it leaches into groundwater and
Like many urban and suburban rivers, the Severn’s biggest
problem is polluted runoff. But computer models estimate
about 22 percent of the Severn River’s excess nitrogen
comes from septic systems, a lot higher than the average
three percent for the broader Chesapeake Bay watershed.
So, while septics may seem a small part of the Bay’s overall
condition, in places such as the Severn River, they are a
The biggest concentration of septics along the Severn is in
communities just upstream of Round Bay—communities like
Herald Harbor. The neighborhood dates back to 1924 and is a
former plantation of peach and apples orchards. The homes
are modest bungalows and split levels with small yards, swing
sets, and tool sheds. Most use septic systems.
For years Anne Arundel County has studied ways to reduce
pollution from septics in neighborhoods such as Herald
Harbor, possibly connecting them to public sewer or replacing
older models with new technology that removes significantly
more nitrogen. But both options are expensive. For instance,
a homeowner at Herald Harbor would have to pay at least
$10,000 to install one of the upgraded systems. The state’s Bay
Restoration Fund (BRF) or “flush fee” provides a small stream
of funding to help, but it’s not nearly enough. Only 52 septics
on the Severn were upgraded through the BRF in 2017.
Meanwhile, Round Bay each summer becomes a dead zone of
low oxygen where fish and other marine life struggle to live.
Hundreds of older upstream septic systems likely are a part of
YOU CAN HELP: Urge your local and federal
legislators to support Bay restoration and demand that
EPA play an active role through increased investment and
imposing consequences to states that fall behind. Visit
cbf.org/take-action for other ways you can help.
About 22 percent of the nitrogen in Maryland’s Severn River
comes from septic systems.
Tom Zolper is the Senior Writer for CBF.
His interests include hiking and playing jazz
standards on the piano.
0 5 2. 5 Miles
(up to 2800
per sq mi)
SOURCE: ANNE ARUNDEL COUN TY/
CHESAPEAKE BAY PROGRAM
SAVE THE BAY 9