This map from DWSD shows the degree of potential old lead service lines in the darker blue areas of the city as well as the higher lead results that are more likely to be found in those areas. After the 2016 testing, the rate of lead in Detroit’s water was found to be at an increase.
During previous sampling periods, MDEQ recommended a sampling protocol which included “pre-stagnation flushing.” Sampling volunteers were instructed to flush the tap for five minutes, stop water use in the house for a minimum of six hours, and collect the first liter of water after the six-hour stagnation period. This practice has been documented to produce lower results than normal household use prior to the stagnation period. In 2016, MDEQ recommended discontinuation of pre-stagnation flushing as part of the sampling protocol. A summary of the findings is available on the City website at www.detroitmi.gov/dwsd under the “Lead and Drinking Water” webpage.