For years, the Baltimore Department of Public Works postponed the dredging of Lake Montebello and a nearby washwater lake, which serve the region’s biggest water treatment plant, allowing both bodies to fill up with sediment and backwash solids – an average of 9,000 pounds of gunk every day.

On February 19, 2025, the long delay appeared to be over.

The Board of Estimates was set that day to approve the first in-depth dredging of the two lakes since 2007 when, before the start of the meeting, DPW withdrew the contract without explanation. Another 18 months would pass before the same company, American Process Group, won the same contract.

When finally approved in July 2026, DPW Director Matthew Garbark called the contract critical to DPW “because it will give us the room in case we need the water from the Susquehanna.”

That possibility is now reality.

Last week DPW began pumping about 30 million gallons per day (MGD) of Susquehanna River water to the Montebello washwater lake in northeast Baltimore, where it was mixed with fresh water coming from the city’s drought-depleted Loch Raven and Prettyboy reservoirs.

And this week about 350,000 households  – those living and working east of I-83 in Baltimore City and Baltimore County and east of Catonsville across South Baltimore – started drawing the first blended water from their faucets and tubs.

Its composition: about one-third river water and two-thirds reservoir water – chlorinated, filtered, fluoridated, pH adjusted and otherwise cleaned up at the Montebello plant before it is piped out to homes and businesses.

Susquehanna River water contains higher levels of sediment, iron, sulfur and organic materials compared to water from reservoirs, hence its natural pale yellow or cloudy brown hue.

“That filth and dirt will be coming down along with the river water”  – Ronald Parks.

More importantly, a 20-mile segment of the pipeline that carries the river water from the Conowingo Dam to Abingdon in Harford County hasn’t been used since 2002, says retired DPW operations engineer Robert Parks.

“That pipeline is full of dirt and grime and sludge. It’s been sitting there for years, and that filth and dirt will be coming down along with the river water,” explained Parks, who worked for 37 years at the Montebello plant and is a blogger and author of Baltimore’s Water Supply History.

How does DPW propose to keep the blended drinking water clear in color, non-metallic in taste, free of odor and safe to consume when its two settling lakes are chock full of sediments and impurities?

Garbark’s earlier answer – to clear out room for the dirtier river water to settle – isn’t possible now. Dredging won’t start until the end of 2026, DPW says, and is expected to take two years to complete.

So the agency is improvising.

Settling the Sediment

First, the river water will go into the wash lake, which is screened from public view within the plant’s campus along Hillen Road. Then it will be piped to Lake Montebello to “provide more opportunity for the sediment to settle” before it is introduced into the treatment plant.

“In addition to naturally settling the sediment in the water, DPW is coordinating with the dredging contractor to install a sediment curtain, which will capture sediment that has not settled in the wash lake or Lake Montebello,” the agency said in response to Brew questions.

In a press release, DPW says it “expects odor and taste issues to be minimal, if they occur at all.”

“The gradual introduction and blending of the Susquehanna River water will help minimize potential changes in taste and odor,” says the agency, which vows to continue to treat and test the blended water to ensure it meets state and federal drinking-water standards.

Parks agrees that lab technicians at Montebello will carefully monitor the blended water to make sure it is safe, but he doubts that Baltimore area household won’t notice changes in color, taste and possibly smell.

When Susquehanna water was last used in 2002, it was blended 50-50 with reservoir water. “People complained about the smell, the taste, the look,” he said. “You could hold up a glass of water and see the turbidity.”

“DPW expects odor and taste issues to be minimal, if they occur at all”  – 10/6/26 DPW press release.

If DPW maintains a one-third river, two-third reservoir ratio, “the water won’t taste as bad as in 2022, but, oh, yeah, it won’t be the same as reservoir water,” Parks said.

As more river water is introduced into the Montebello plant, sand filters and other equipment will need to be backwashed and cleaned more frequently, sending more dirt particles and other plant byproducts into the wash lake.

DPW says it has already lowered the level of the wash lake to handle the river water, which means more discharges into Tiffany Run.

That tunneled stream – which famously cracked apart in November 2022, causing a sinkhole that cost taxpayers $30.4 million to repair – flows into Herring Run. And Herring Run empties into Back River and the Chesapeake Bay.

Keeping within its Permit

This presents another potential problem for DPW: will discharges from the filtration plant violate its National Pollutant Discharge Elimination System (NPDES) permit?

The Montebello filtration plant is under U.S. Environmental Protection Agency rules to limit discharges into Herring Run, which continues to suffer from untreated sewage spills during heavy downpours.

Over the last year, the Montebello plant was cited by EPA for five permit violations, the latest on August 28 involving suspended solids and pH acidity noncompliance.

“That’s always been an issue keeping within the permit. That’s one reason why dredging is so important. The washwater lake is supposed to be dredged every five years, and Lake Montebello every 30 years,” Parks said.

But the wash lake was last partially dredged in 2016, he said, and one third of Lake Montebello was last dredged in 2005-07. “When the wash lake was last dredged, where did the muck go? It was dumped into Lake Montebello!”

“When the wash lake was last dredged, where did the muck go? It was dumped into Lake Montebello”  – Ronald Parks.

In many ways, the fate of the region’s water supply rests with Mother Nature. If substantial rainfall comes this fall and winter to Baltimore, and water levels at the city’s three reservoirs – Loch Raven, Prettyboy and Liberty – are restored, water from the Susquehanna will no longer be needed.

Parks, for one, hopes that happens as soon as possible.

When he was researching his book, he ventured up the Susquehanna to its source near Cooperstown, N.Y., counting 13 wastewater treatment plants along the way and, most vividly, encountering an abandoned coal mine used for the illegal dumping of chemicals.

“You could see the brown oil and sludge leaking into the river,” he recalled. “This is not the kind of water you really want to drink.”