Flint residents who use water filters in their homes should flush their pipes for longer periods each morning and especially if they haven’t used their water for some time to reduce bacteria growth, two university professors said Tuesday.
The researchers from Michigan universities and hospitals was released to help residents cope with the long-running lead contamination crisis. While lead levels in water are now below the federal action standard, they remain high enough that experts advise residents not to use their taps without a filter.
The two researchers, Nancy Love of the University of Michigan and Shawn McElmurry of Wayne State University, plan to discuss these findings with Flint Mayor Karen Weaver Tuesday at 6:30 p.m. on WFLT 1420 AM Flint radio.
More than 100,000 filters mounted to faucets and several hundred cartridges have been distributed in Flint since 2015, when the crisis was first acknowledged. They are designed to remove metals, such as lead, chlorine, which is added to kill bacteria.
But there is concern through studies that they can also support the growth of bacteria in water.
The recommendations are:
■Turn the filter switch to the position so it directs water away from the filter through the bypass and then run the faucet until the water temperature cools, which could take several minutes. This step avoids using water that has been sitting stagnant in the home's plumbing and usually contains little chlorine. It sends the water with the highest bacterial counts down the drain rather than through the filter, stemming bacterial growth.
■Run filtered water for 15 seconds before collecting any to use.
The two researches said in a news release that all drinking water contains some bacteria but that they have not linked bacteria to any illnesses. But they said they are investigating “whether any harmful bacteria are present in Flint-area filters.”
“Flushing as we recommend can reduce the bacteria levels in water by 10 or 100 times,” said Love, a UM professor of civil and environmental engineering who led the filter research. “That said, we know that Flint residents’ water bills are among the highest in the country, and this approach could create additional financial hardship.”
The research was coordinated with the Genesee County Medical Society and the Flint’s mayor’s office. It was backed by grants to UM and Wayne State from the National Science Foundation.