In view of the foregoing facts I find myself compelled to report to your Honorable Board my firm conviction that there is danger, both constant and grave, in the water of the Merrimack River at Lowell.”

William T. Sedgwick
Professor of Biology at MIT
Biologist to State Board of Health
April 1891

As Christmas approached in December 1890, doctors in Lowell detected an alarming spike in the number of deaths from Typhoid fever. Although much remained unknown about the cause and transmission of the disease, doctors and scientists were by then pretty certain it came from drinking tainted water. With the city of Lowell having just spent hundreds of thousands of dollars on a sophisticated municipal water supply that drew from the Merrimack River, the Lowell Water Board felt compelled to investigate the cause of the epidemic. It hired William Sedgwick, a professor of biology at MIT and the official biologist for the State Board of Health.

Sedgwick came to Lowell, conducted an extensive investigation, and delivered a balanced report to the Lowell Water Board in April 1891 that identified drinking water from the Merrimack River as the likely cause of the crisis. But even Sedgwick, who went on to found the Harvard/MIT School of Public Health and is considered to be one of the founders of the field of public health in America, left some wiggle room in his report.

By 1890 it was widely accepted that Typhoid fever was caused by drinking water that had been contaminated with sewage. Left unanswered was the question of whether there was a “safe” level of contamination. It was thought that since the bacteria that caused Typhoid was a living thing, it would die after long exposure in cool water and that dead bacteria was harmless. It was also believed that the continuous addition of new, “pure” water into the river from ground water and tributary streams would “dilute” the amount of bacteria in the water to a level that would make it safe to drink.

Sedgwick pretty much shot down this “safe enough” theory by observing that even if Typhoid-causing bacteria was only rarely present in Lowell’s drinking water, that would give little comfort to the unfortunate person who ended up with that “rare” bacteria in their drinking glass and thereby contracted a fatal illness.

The crack that Sedgwick left open was that the amount of bacteria in the Merrimack River at the time of the epidemic was abnormally high with the implication that at almost every other time the water was safe to drink. He added the caveat, “sewage in city water has undergone great dilution and probably some purification but concerning the latter subject we are still very much in the dark.”

Still, Sedgwick himself did not seem to believe the Merrimack water was safe to drink. Using statistics, he showed that the rate of death from Typhoid fever in Lowell and Lawrence over a multiyear period was more than double that in Boston, Worcester, Springfield, and Lynn – all industrial communities with the same public health challenges as Lowell and Lawrence. He also noted that death rates from other causes were comparable in all six cities. It was only for Typhoid that Lowell and Lawrence stood out. Sedgwick wrote that “these are the only two cities in the state which draw their water for drinking from a river into which, within 20 miles above, sewage is publicly discharged.”

Two years after Professor Sedgwick issued his dire warning to the Lowell Water Board, municipal officials in Hamburg, Germany, began experiments that added chlorine to drinking water. In 1897, Maidstone, England, became the first city in the world to fully chlorinate its drinking water supply. The first US water supply to be fully chlorinated was in Jersey City, New Jersey, but that was not until 1908.

But the Lowell Water Board could not wait for chemical treatment of drinking water to become feasible. Instead, it immediately began to investigate drawing Lowell’s drinking water supply from newly drilled wells in Pawtucketville. Water from there could still use the expensive infrastructure of pipes, pump stations, and reservoirs that the city had created in the preceding decades. These so-called Boulevard wells provided most of the city’s drinking water for the coming decades.