Baltimore details series of aging infrastructure failures that caused E. coli contamination in drinking water over Labor Day weekend

Baltimore’s Department of Public Works on Thursday spelled out the most probable cause of E. coli contamination in West Baltimore’s drinking water over Labor Day weekend: a string of failures of aging infrastructure.

The city’s explanation starts with a sinkhole on North Avenue in early July, which occurred when a 115-year-old stone tunnel became overwhelmed by stormwater and collapsed. After the city had to complete another emergency water system repair on Kirk Avenue, officials said, the source of West Baltimore’s drinking water changed primarily to Lake Ashburton.


But there also was a sinkhole at the toe of the dam at Lake Ashburton in February, due to a leaking water main. That main, installed in 1925, had to be taken offline.

The combination of all those factors meant that chlorination levels in the water system were reduced, leading up to the discovery of E. coli in some West Baltimore water.


“It was a result of aging infrastructure,” said Department of Public Works Director Jason Mitchell, “something that this city and all cities this age are dealing with.”

In all, three drinking water sampling sites in the city tested positive for E. coli — each in a small area near Harlem Park in West Baltimore, an already economically disadvantaged section of the city. The city imposed a boil water advisory for residents across a broad swath of the city and into Baltimore County, which is served by the city water system.

Extensive testing around the city and county subsequently didn’t turn up any other positive tests, officials have said. And within a week, the three positive sites were testing negative again, and the boil water advisory was lifted.

Experts who spoke to The Baltimore Sun prior to the city’s announcement of the cause said bacteria can build up in underused areas of the water system. Changes in water pressure in the extensive system of water mains and pipes can cause that bacteria to bleed into other areas of the system, and therefore to peoples’ faucets.

During a City Council hearing Thursday about the crisis, Public Works officials laid out their theory for the contamination for the first time.

After the infrastructure failures on North and Kirk avenues, the city’s Vernon Pumping Station was sending treated water to West Baltimore residents exclusively from Druid Lake in Druid Hill Park, rather than receiving some directly from the water treatment plant. Officials grew concerned that the lake’s water levels would be reduced too much, and decided to shut down the pumping station.

A different pumping station in the city, the Hillen Pumping Station, was turned on so that water pressure throughout the drinking water system would be maintained. But that’s also when the primary source of West Baltimore’s water switched to Lake Ashburton, where there was a problematic water main.

On Labor Day, as the city announced the E. coli contamination and the boil water advisory, the Vernon Pumping Station was brought back online. The city also flushed out the water in the impacted area, increasing the chlorination and letting fire hydrants spew water to remove what could have been contaminated.


In the wake of the contamination, many City Council members expressed concern about the way it was communicated to the community. The contamination was confirmed on Sunday Sept. 4, but not reported via social media channels Twitter and Nextdoor until the next morning.

And though city officials have said they knocked on all doors in the affected area to alert residents, not all residents have said they received the communication, said Councilman Isaac “Yitzy” Schleifer, who represents the city’s fifth district. But when Schleifer asked about the precise door-knocking effort at Thursday’s hearing, Mitchell said he didn’t have the information at hand. And no one from the department’s three-person communications team had attended the hearing to answer questions.

“The real concern that you’ve been hearing is the communication,” Schleifer said. “So I really would like to understand why there’s nobody from the communications department here to explain to us why this entire situation did not get put out to the public sooner than it did.”

City Administrator Chris Shorter said that Mitchell was accepting questions about the communications effort due to “changes in personnel” happening within that team in DPW.

With that, the hearing concluded after about one hour, far more rapidly than an initial four-hour hearing about the E. coli contamination.

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At that first hearing two weeks ago, Public Works officials laid out a timeline of the crisis. The department first learned that one of its drinking water sampling sites — Baltimore City Fire station Engine No. 8 in Harlem Park — had tested positive for E. coli at about 11:30 a.m. Saturday, Sept. 3.


But the sample site had to be retested to confirm the accuracy of the result. The department received a second positive result at 9 a.m. Sept. 4. By that afternoon, two sampling sites upstream and downstream of Engine No. 8 had tested positive as well.

The crisis however didn’t come to light for the public until the next morning, when the Department’s Twitter account shared that three sites in the city had tested positive for E. coli.

The messages stated that “residents may want to consider boiling any water used from faucets,” but failed to specify where.

Officials didn’t release an official boil water advisory, accompanied by a map of the affected area until late that afternoon.

A required boil advisory covered a roughly 56-block area of West Baltimore, and a precautionary advisory stretched down into Baltimore County. But no sites beyond the original three ever tested positive for E. coli.

After those three sites tested negative for E. coli repeatedly, the boil water advisory was lifted in its entirety. Baltimore Mayor Brandon Scott announced a 25% discount on the next round of water bills citywide.