As the population grew in Seattle and its environs, nearby springs and small companies could not provide the necessary water supply. The need for an adequate system became more apparent after the fire of 1889 and a number of typhoid outbreaks due to contaminated water in 1891 and 1909.
While the management of Seattle's water system primarily involved the Water and Engineering Departments, the Health Department focused on the pollution and contamination that threatened the public's health.
In 1895, Seattle voters approved a $1,250,000 bond issue to buy a water source on the Cedar River and to construct a gravity-flow system to conduct water to the city. However, the logging industry, the railroad and human presence in the watershed area still posed threats to the purity of this water supply.
Four patrolmen, or inspectors, examined sanitary conditions throughout the watershed. Patrol duties included assuring that: no one entered the watershed without a permit; all area employees were immunized against typhoid; temporary worker camps were provided with proper sewage and disposal systems; hobo shacks were removed; all toilets were locked on trains which passed through; and, no fecal matter, debris or dead animals were in the area. The Health Department collected samples from the river and its tributaries each week for bacteriological analysis. Protecting the watershed against pollution was a Health Department responsibility until 1944.
The Department also participated in efforts to keep public recreation areas sanitary. Various substances were used to treat beaches that had been polluted by sewage, including chloride of lime, liquid chlorine gas, and copper sulfate to keep down algae growths.