On Monday, reports of Bloomington’s tap water tasting and smelling bad continued to come into the city’s uReport system.
One example: “The smell and taste of the water has been absolutely disgusting for at least three weeks. Has the cause been found yet? It makes me nauseated to run the tap in my home.”
At Monday’s meeting of the utilities service board (USB), city of Bloomington utilities (CBU) director Vic Kelson told members the taste and odor issue had essentially been solved. But it will take a while for the good tasting water to work its way through the distribution system, Kelson added.
A point of emphasis in communications from CBU over the last several days has been that the bad taste and smell pose no danger to human health.
The cause of the dirt or fish taste, according to Kelson, is naturally occurring chemicals that are produced by algal blooms in Lake Monroe—geosmin and methyl-isoborneol (MIB).
Kelson said the long hot spell with no rain towards the end of the summer had led to a large algal bloom in Lake Monroe, the source of Bloomington’s drinking water. But results from an outside lab received Monday indicated the algal bloom has diminished dramatically since last week, Kelson said.
Water treatment plant staff had increased the feed rate of powdered activated carbon (PAC), which helps with the odor, Kelson said. The amount of additional PAC will be eased off as the quality of the water coming into the plant continues to improve, Kelson said. PAC started getting added routinely to the drinking water mix in 2017.
That doesn’t mean all of Bloomington’s water will start tasting and smelling better at the same time. Starting at the water treatment plant at Lake Monroe, for a drop of water to make its way through the pipes to the farthest point in the distribution system takes seven to 10 days, Kelson said.
Kelson gave some anecdotal evidence for the lag time, based on the water plant superintendent’s experience. The superintendent reported that the water didn’t taste bad at his house until late last week, but he lives pretty far out in the distribution system, Kelson said.
Kelson thinks it’s going to be another week or so before the bad taste has worked its way through the distribution system.
Kelson told the USB that this year is the first time since 2016 that CBU has had any taste and odor complaints at all. Previously, reports of the tap water tasting like the lake or fish came in every summer, through most of the summer, Kelson said.
For next year, CBU is looking at ways to be “a little bit more aggressive” to get ahead of the problem, Kelson said. This year, the staff increased the feed rate of powdered activated carbon (PAC).
PAC has been added to Bloomington’s water since 2017, and it’s meant to address the issue of disinfection byproducts (DBPs). But PAC has the positive side effect of removing bad taste and smell.
CBU’s communications manager Holly McLauchlin wrote in response to an emailed question from The B Square, that when CBU received its first complaints on Sept. 10, adding more PAC was not the immediate response. That’s because CBU needed first to determine for sure what was causing the problem.
McLauchlin also noted that additional PAC is expensive. It’s not just the cost of the material that’s a factor, but also the wear and tear on the treatment equipment caused by PAC, according to McLauchlin. She added that PAC is not a cure-all. “Lake taste is notoriously hard to get out of the water,” McLauchlin wrote.
Could CBU approach the problem by drawing water from a level of the lake that’s not as affected by algal blooms?
Responding to an emailed question from The B Square, McLauchlin wrote that there are three intake levels for water from the lake. CBU uses the mid-level intake. According to McLauchlin. CBU has used the upper one occasionally. But the deep intake has not been used a single time since 1968, according to McLauchlin. At deeper levels, iron is more prevalent, and iron is more of a nuisance than lake taste, according to McLauchlin.
At the water treatment plant, Kelson told the USB on Monday, the water now tastes fine. “We’re tasting the water and smelling the water at the plant every single day—I think it’s every hour of every day.” Kelson continued, “We haven’t had any issues at the plant for several days now, maybe a week.”
Kelson added, “We’re optimistic that it’s all going to clear out of the system fairly quickly. We’ve also done some flushing of some of the lines in the system.”