As Rain Fell, Sewage Systems Across The Bay Region Buckled

ANNAPOLIS, Md. – Intense rainfall Jan. 9–10 represented a real-life stress test for sewage treatment systems across the Chesapeake Bay region. Many failed.

Millions of gallons of diluted raw sewage gushed out of faulty pipes and antiquated collection systems. The cumulative effect was like a gigantic toilet flushing into the streams and rivers that drain into America’s largest estuary.

Wastewater treatment plants are often cited as one of the region’s biggest success stories as state-of-the-art pollution-scrubbing technologies installed at hundreds of facilities have reduced their nitrogen discharges by 45% since 2009, according to the state-federal Chesapeake Bay Program.

But many cities and counties rely on outdated “combined sewer” systems to transport waste to treatment plants. These systems collect rainfall that flows into storm drains along city streets and combine it with everything that’s flushed down toilets or washed down indoor drains. Under normal conditions, the combined stormwater and sewage systems flow to wastewater treatment plants before getting discharged into a river.

But to prevent backups into people’s homes or at wastewater facilities during monumental rainfall events, those systems are designed to let the watered-down sewage overflow into local waterways.

Other, more modern “sanitary sewer” systems keep stormwater and sewage separated but can still be vulnerable to rain-induced overflows. Rainwater can seep into the systems through some combination of cracked pipes, faulty manhole covers or improperly connected downspouts.

The Bay Journal obtained sewer overflow records through public information requests from the three states with the most territory within the Bay’s drainage basin: Maryland, Pennsylvania and Virginia. The analysis concentrated on the Jan. 9–10 storm as an example of the rainfall expected as extreme storms become more common.

Over a span of about 14 hours, the storm dumped up to 3 inches of rain. That’s about as much precipitation as the Bay region would typically gets during an entire January.

Across the portions of the three states lying within the Bay’s drainage area, municipal wastewater facilities released at least 296 million gallons of sewage-laden stormwater during the storm and its aftermath, the records show. The actual total is almost certainly higher because several communities said they lacked the means to estimate how much wastewater escaped, often citing logistical problems with accessing spill locations during flooding.

Pennsylvania easily led the way, with 58 municipalities reporting the release of about 240 million gallons of mixed stormwater and sewage. Maryland recorded about 36 million gallons in spills, followed by Virginia with 20 million gallons.

Pennsylvania’s outlier status owes largely to its having more combined sewer systems than any state — about 17% of the nation’s total.

The state Department of Environmental Protection says it has made significant strides in reducing the amount of raw sewage overflows. For example, the number of combined sewer systems in the state has been reduced from 150 to 120, said DEP spokesman Neil Shader. And the number of discharge points where overflow pollution is released has fallen from 1,900 to 1,584.

But the two-day January rainstorm highlighted just how much tainted water still escapes the systems.

The combined sewer systems accounted for 236 million gallons, or 98%, of the total amount spilled in the state during the storm. Altoona released almost 59 million gallons, Hazleton 56 million gallons and Harrisburg 48.6 million gallons.

“These sudden bursts of storms … can just wipe out all the [combined sewer] improvements we’ve seen in a year,” said Charlotte Katzenmoyer, CEO of Capital Region Water, which is under a consent decree to reduce combined sewer overflows from the Harrisburg area into the Susquehanna River. “We’re fighting climate change.”

Still, the impact on the Bay is relatively small. Bay Program computer models suggest that combined sewer overflows contribute an average of 1.2 million pounds of nitrogen annually to the Bay, about half of 1% of the total. That’s down about 30% over the past few decades because of actions such as decoupling the wastewater and stormwater systems and expanding holding capacity.

But the spills can inflict serious environmental damage to local streams and rivers. And the bacteria-laden slurry can pose serious health threats to people and pets that come into contact with water.

Shader said DEP anticipates municipalities will account for stronger storms as they adjust their long-term plans to control overflows in coming years.

Those changes come at a cost, though.

The EPA and DEP sued Capital Region Water, resulting in a modified consent decree in 2023. Capital Water agreed to develop a plan to drastically cut sewer overflows by separating some sewage and stormwater pipes, replacing or lining leaking pipes and adding temporary underground storage for stormwater so it won’t mix with untreated sewage during storms.

A key part of the long-term project is so-called green infrastructure. Examples are rain gardens, porous basketball courts and parking areas, and storing water under tree-lined sidewalks and a soccer field.

According to Katzenmoyer, the utility has spent $200 million over the last 10 years on the combined sewer overflow problem and plans to spend $250 million more over the next 10 years. But she stresses that Harrisburg is a cash-strapped city, and the immensity of the problem simply can’t be borne by ratepayers.

“Yes, EPA is pushing us. That’s their job,” she said. “And we want to do the right thing. It’s just a matter of what we can afford.”

In most communities, there’s no easy fix. Nearly every city with sanitary or combined sewer overflow problems faces obstacles with acquiring funding and overcoming the complexities involved with overhauling a sewage system often built many decades ago. Efforts to stop the spills can drag on for years, according to a U.S. Governmental Accountability Office report released last year.

One of the places highlighted in the report was Cumberland in western Maryland. The city of 45,000 people first submitted a plan to the state in 1994. The plan has evolved into a series of projects that seek to eliminate or capture at least 85% of the combined sewer discharge. Over the years, the city has invested about $60 million and, as of the report’s publication, expects to spend another $90 million to finish the work.

“Our best guess for the start of construction is 2028 and final completion in 2031,” City Administrator Jeffrey Silka said in an email. “The City will need several more years in order to finish our work due to the massive scope/cost of the projects.”

A combination of rainfall from the Jan. 9-10 storm and snow melt overloaded Cumberland’s beleaguered wastewater system, resulting in nearly 7 million gallons of spilled sewage.