Detroit was founded at the narrowest point of the Detroit River, an abundant source of clean drinking water. Early settlers relied on a rudimentary water distribution system delivering daily to residents by horse-drawn carts. As the city grew, residents began drilling wells to supplement river sources. But the wells came up dry, and later attempts to create reservoirs to capture surface water also failed. Detroit turned to the example of major metropolises of the east, like New York, Philadelphia, and Pittsburgh, by creating pumping systems to bring clean river water to their residents.

In the 1840s, residents often dumped waste in the river, compromising Detroit’s water quality and causing water-borne diseases like typhoid fever. Not until the early 1900s did Detroit city engineers recognize the link between wastewater and illnesses. In 1912, the U.S. Public Health Service issued a mandate that required Detroit to disinfect all distributed water with calcium hypochlorite.

In 1916, treatment switched to chlorine, a more effective disinfectant. Detroit also constructed a new water intake point well away from the city’s wastewater dumping area, especially critical as the automotive industry began its explosive growth. Detroit’s population boomed from the car industry, so quickly that city planners rushed to install cast iron mains without a coherent plan. Pipelines clustered on top of each other in some sections of the city, while other areas lacked any mains at all.

Today, the Great Lakes Water Authority (GLWA) treats all Detroit drinking water and transports it to the city distribution system through more than 2,700 miles of water mains. The system sources water from intakes located in the Detroit River: one to the north, near the inlet of Lake St. Clair, and one to the south, near Lake Erie. The third intake is located in Lake Huron. Four plants treat source water drawn from the Detroit River intakes. The fifth water treatment plant, located in St. Clair County, uses source water drawn from Lake Huron.

Older cast iron pipes, like the ones originally installed, are susceptible to corrosion and biofilm contamination. To combat corrosion, treatment plants add orthophosphate, shown to prevent the leaching of lead into Detroit drinking water. Even with orthophosphate, chemical reactions can create clusters of pipe deterioration and bacteria along the inside of the pipe, resulting in “rotten egg” taste and smell.

Detroit has one of the nation’s strictest policies regarding lead and copper contamination. The recent Detroit Water Quality report shows that water leaving treatment plants does not contain lead, nor do the water mains. However, corrosion in service lines and household plumbing may still contaminate Detroit drinking water with elevated levels of lead.