Once, Baltimore drinking water was a constant danger.

Poor sanitation left the water dirty and often unfit to drink. In the early 20th century, “summer diarrhea,” a seasonal rise of gastrointestinal illness caused by microorganisms, was a leading cause of death among infants and children.

Such dangers have become a distant memory in Baltimore, at least until city officials detected E. coli in the tap water. After a weeklong scare, the city announced Friday the water was again safe to drink, but the issue renewed attention to Baltimore’s famous, yet aging, municipal water system, long a source of civic pride and stability.

It was in Baltimore that a Johns Hopkins-trained sanitary engineer developed the methods to disinfect municipal water systems and pipe clean, safe drinking water across a city. For his breakthroughs in the early 20th century, Abel Wolman became known as the father of clean water, and Baltimore earned a reputation as a world leader in municipal water systems.

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In the decades since, the system Wolman built has quietly, dependably, carried on. Families had little reason to question, or even consider, the water coming from their faucets.

The tap water here is “kind of sacrosanct,” said Rona Kobell, co-founder of the Baltimore-based Environmental Justice Journalism Initiative. “As messed up as Baltimore is in many respects, the drinking water has always been top notch.”

In fact, families may have felt worse shock and confusion because they’re used to having safe, reliable drinking water, she said.

In the early 1900s, however, bacteria in the drinking water sickened adults and children across the city. An outbreak of typhoid fever in the spring of 1906 caused a panic in North Baltimore and killed nearly 200 people.

Scientists had experimented with chemicals to kill bacteria in the drinking water, but it was Wolman and his Hopkins classmate Linn Enslow who developed the formula for the amount of chlorine needed to safely treat a source of water. They applied the technique to the local drinking water and cases of typhoid plunged. Other cities adopted their methods.

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A history of Wolman published by the Johns Hopkins Bloomberg School of Public Health cites statistics from the American Water Works Association showing typhoid cases per 100,000 people dropped in the U.S. from 16.2 to 2.5 between 1913 and 1936.

“The annual number of deaths from typhoid in this country went from thousands to basically zero in a fairly short time, like a couple of years,” said John Boland, an engineer and retired Hopkins professor who had an office down the hall from Wolman.

The breakthrough launched Wolman’s career. He went on to posts as a sanitary engineer in state and federal agencies and helped design the water systems in cities across the U.S., even advising foreign governments such as Sri Lanka, Brazil and Israel, according to the Hopkins history.

The first half of the 20th century brought a golden age for municipal water systems, said Stephen Gorden, a commissioner in Cumberland County, Maine, and past president of the American Water Works Association.

“The big cities were just outstanding in water treatment. They had the respect from the public, and the public wasn’t afraid to spend money to do research and keep the drinking water safe and make sure there was an adequate supply,” he said.

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An aerial view of the southernmost section of Liberty Reservoir.
An aerial view of the southernmost section of Liberty Reservoir, which helps supply Baltimore's water system. (Matthew Binebrink/Creative Commons)

That investment has diminished in more recent decades and cities across the country are now grappling with aging infrastructure.

Last month, flooding knocked out a water treatment plant in Jackson, Mississippi, leaving 150,000 residents without water. Communities in Harris County, Texas; Jacksonville, Florida; and Doña Ana County, New Mexico, have advised residents to boil their water following positive test results for E. coli or coliform in recent weeks.

Baltimore has more than 4,000 miles of water mains with an average age of 75, according to the Department of Public Works. The department has traced some old, cast-iron mains back to the Civil War years.

With such aging infrastructure, leaks and breaks are frequent and may cause dirty groundwater to flow in and contaminate drinking water. City officials said they are investigating whether construction projects in West Baltimore to replace water mains and repair valves may have caused the recent contamination.

City officials have said they know of no one who fell ill from the water.

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Gorden, for one, urged Baltimore residents not to let the incident cause them to doubt a water system held in high regard in his profession.

“Have faith in your operation of Baltimore water,” he said. “People in the industry are very diligent. If you really think about it, if you didn’t have a great water system, you would not have a city.”

Banner reporters Adam Willis and Sophie Kasakove contributed to this article.

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