Chlorination of Jersey City's water supply

In 1899 Jersey City contracted with Patrick H. Flynn, for a new water supply that the city could later buy for $7,595,000. Flynn's rights passed to the Jersey City Water Supply Company, which built the works, and the contract required the water to be "pure and wholesome". Water from a reservoir at Boonton, on the Rockaway River, began flowing to the city on 23 May 1904.

The city soon objected to its quality and went to court in August 1905. The catchment above Boonton covered 122.5 square miles and held 169 people per square mile, a heavy population for a drinking supply, and the river at and below the town of Dover was highly polluted. The company argued that storage in the reservoir purified the water. Its sanitary adviser, John L. Leal, a physician trained in bacteriology, testified that about half of typhoid germs die within five days and 99 percent within three weeks. On 1 May 1908 Vice Chancellor Frederic W. Stevens found that two or three times a year river water could reach the city's reservoirs in two or three days, and held that works fit to deliver pure and wholesome water for only part of the year did not fulfil the contract.

Seven weeks later, on 19 June, Leal hired the sanitary engineer George W. Fuller to build a chlorination plant at the reservoir. Fuller designed it and supervised its construction in 99 days. Dilute solutions of chloride of lime ran by gravity into the water. The plant went into service on 26 September 1908, treating an average of 40 million gallons a day, and the Boonton supply has been chlorinated continuously since.

It was the first routine disinfection of a community water supply in the United States. The method was effective and cheap, and within a decade thousands of American cities and towns had adopted it. Typhoid in the United States fell from about 100 cases per 100,000 people in 1900 to 33.8 in 1920.