Bloomington residents might have noticed the return of an odd taste in their tap water this past week, but according to city utilities and water experts, it isn’t dangerous to your health.
Todd Royer, a professor at IU’s O’Neill School of Public and Environmental affairs, said the compounds geosmin and MIB produced by bacteria and algae in Lake Monroe are the culprits. Warmer temperatures at the beginning of fall caused the creation of the flavor a bit later in the year than previous appearances.
“Those exceptionally warm days that we had sort of extended the summer period into autumn,” he said. “And in doing that, they sort of prolong the bacterial season, particularly for the cyanobacteria, and that has sort of delayed when the smell and taste have appeared in our in our water supply.”
Vic Kelson, Director of Utilities for Bloomington, said that the city has been working out how to solve the problem for the better part of a year.
“What we did decide to do is change the kind of activated carbon that we feed in our treatment process to a different version, it's actually made from husks of coconuts,” he said. “And we are seeing that it is doing a better job than the version of activated carbon we were using last year, and it is reducing the MIB concentration from lab significantly but not enough, apparently, to get it to where the taste completely doesn't appear.”
Kelson said that fixing the problem entirely is too cost prohibitive for a problem faced for a short period each year.
“Obviously, we want our water to taste good all the time,” he said. “But there are always going to be limits on how much our community is going to be willing to spend to deal with a couple of weeks of this.”
Kelson also expressed concerns that because of climate change, we’ll continue to see these odor-causing bacteria popping up in the city’s water supply.
Read more: Stinky water is not making people sick in Bloomington
