Baltimore officials identified a likely cause of the E. coli contamination that left much of West Baltimore under a water boil advisory earlier this month, pointing to a series of failures stemming from the city’s aging water infrastructure.

The explanation, which officials laid out in an hearing on the episode before the City Council Thursday, comes a few weeks after the city Department of Public Works warned residents of possible E. coli contamination in the Harlem Park and Sandtown-Winchester neighborhoods of West Baltimore. The city received positive tests of bacteria in the water system on Saturday, Sept. 3, but residents didn’t learn about the contamination until two days later, on Labor Day morning.

A targeted area of about 1,500 homes and businesses was put under a mandatory boil-water advisory, while tens of thousands more residents in West Baltimore and parts of Baltimore County were told to boil their water as a precaution. The city lifted its boil-water advisory on Friday, Sept. 9, after repeatedly flushing the system and finding no remaining contamination.

At the time the city decided to give the all clear, it hadn’t identified the source of the contamination. That changed Thursday, when DPW officials laid out their theory of the most likely cause.

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What caused Baltimore’s E. coli contamination?

A combination of three factors stemming from old water infrastructure compromised the safety of the city’s system ahead of the recent contamination, taking water mains offline and contributing to lower chlorine levels that may have allowed bacteria to get into the system, Yosef Kebede, head of the public works department’s water and wastewater bureau told city council members on Thursday.

In early July, a North Avenue storm tunnel dating to 1898 collapsed, opening up a sinkhole that led to several homes being condemned. Separately, the city had to do an emergency replacement on a 107-year-old water main valve along Kirk Avenue. These two issues took large water mains out of service and meant the Vernon Pumping Station near Druid Hill Park had to draw its water exclusively from Druid Lake, pulling the water there down to a potentially unsafe level.

In response, the city shut off the pump station in late August, and the city switched West Baltimore’s drinking water source to Lake Ashburton. That proved problematic, however: another sinkhole near Lake Ashburton’s dam from February forced the city to abandon a water main there dating back to 1925.

This chain of issues resulted in lower chlorine content, a flaw in the water system’s armor that public works officials suggested may have allowed E. coli and coliform to contaminate the flow in parts of West Baltimore.

“It was the result of aging infrastructure,” Department of Public Works Director Jason Mitchell told council members, a challenge he noted is facing many other cities in addition to Baltimore.

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Why were contaminants only found in West Baltimore?

Public Works discovered bacteria at three testing sites in West Baltimore over Labor Day weekend, but why the contamination was concentrated only in that part of the city — a predominantly Black area that has dealt with decades of depopulation and disinvestment — isn’t entirely clear.

Kebede told council members that the agency had to turn to Lake Ashburton as the water source for West Baltimore, where the abandoned pipeline led to fewer safeguards and lower chlorine levels in the flow.

Still, different zones of the city’s water system are interconnected through mains and valves, a design that Councilwoman Odette Ramos noted poses concerns for situations like the E. coli incident. The city has to be “extra careful” to make sure that contamination in one zone of the system doesn’t infiltrate another, she said.

The city’s system of valves allows Public Workd to isolate issues to certain areas by cutting off the flow of water to other parts of the city, Kebede said.

What is the city doing to prevent this from happening again?

With the average age of Baltimore’s water mains at 75 years old, and many pipes exceeding 100 years, the aging system has strained the city’s ability to maintain and repair it. Like many older cities, Baltimore is in a race against the clock to keep up its water infrastructure, aiming to replace 15 miles of pipe across its 4,000 mile system each year.

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DPW officials said Thursday that expensive investments to cover water sources at both Druid Hill Lake and Lake Ashburton will insulate them from outside hazards, making contamination “very unlikely.” The bulk of the $330 million in new funding Baltimore received from the state department of environment to improve its drinking water system since 2014 has gone towards these projects.

Kebede also laid out several steps the city is taking to prevent possible infrastructure failures. In West Baltimore, DPW is accelerating assessments and replacements of water mains and other water infrastructure, he said.

The city is hopeful that some of the money it receives through the federal infrastructure bill passed in 2021 will help address these problems of aging infrastructure, but the the funds are likely to fall short: nationwide, the nation’s drinking water utilities need over $472 billion in capital improvements over the next 20 years, according to the U.S. Environmental Protection Agency. The infrastructure bill dedicates just $11.7 billion that states can use towards aging water systems.

What else went wrong?

Thursday’s hearing was the second held by city council on DPW’s response to the Labor Day weekend E. coli scare. At the initial hearing earlier this month, city council members grilled Public Works on its handling of the incident, honing in on the department’s communication to residents, while agencys officials conceded some missteps.

Councilman Isaac “Yitzy” Schleifer reiterated Thursday that the “real concern” around the E. coli incident was not the contamination itself, which can happen in other places, but the failure of the city to clearly communicate the issue to the public. In addition to alerting residents to the contamination through social media channels, DPW has said that it knocked on doors across the impacted area on Labor Day to get the word out, though Schleifer said many residents have reported they were never informed.

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No members of the agency’s communications staff were present for Thursday’s hearing, and City Administrator Chris Shorter said the agency would not be answering questions on the topic due to “changes in personnel” underway in that division.

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Adam Willis covers city government for The Banner, including the impacts of the large COVID-19 stimulus package that Baltimore received from the federal government.

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