Does the water coming from your faucets in Bloomington have a slightly different taste and smell lately?
Well, the Bloomington Water Department says there’s no cause for alarm.
Water Director Ed Andrews said the department made a move Friday to switch its primary water supply source from Lake Bloomington to Evergreen Lake – largely for volume concerns.
“Lake Bloomington is almost 8 feet below its normal operating pool, and Evergreen is only 2.7 feet drawn down below its normal operating pool,” said Andrews. “So in order to have an effective balance between available water, we routinely switch between the two lakes.”
Andrews said a temporary switch had already been planned to accommodate some maintenance work, but the disparity in the operating pools further swayed the switch to Evergreen Lake. The city posted notices on social media to address anticipated reaction to the taste and odor changes.
Andrews said the detectable taste and smell differences are predominantly caused by the naturally occurring compounds geosmin and methylisoborneol [MIB]. But he notes the minute particles in the water remain within the requirements.
“Our regulated levels, as far as chlorine and any other trace elements, are all within the standard operating procedures, and taste and odor fall under the nuisance category. It’s not a health component,” he said.
“I’m the first to admit, I would rather have those trace compounds knocked down as much as possible.”
Andrews said the city switches between the lakes regularly, and also has the ability to use a blend from both lakes in its water supply.
“Seasonally, we get turnover in the lake and it starts to elevate those compounds where you get a real pronounced musky, earthy taste to the water. Last fall, when we headed into September, we were running a 60-40 blend between Evergreen and Bloomington,” said Andrews.
Andrews said the city has plans to implement powdered activated charcoal, or “PAC,” equipment to assist with filtration, pending anticipated Bloomington City Council approval later this year.
“Right now today, we have filter beds that have granulated activated charcoal [GAC] and sand filtration. They layer that in, and we have multiple filter beds up at the plant, and that’s part of that filtration process. The GAC knocks it back some, but obviously not to the degree that we would desire,” he said.
Andrews also noted a diminished amount of rainfall over the past year has led to the lower than normal operating pools at Lake Bloomington and Evergreen Lake.
“We are in a water deficit right now,” he said, referencing National Oceanic and Atmospheric Administration reports for January. “We should have had 2.4 inches of rain for the month on average, and we only had 0.6.
“We were primarily pumping from [Lake] Bloomington, hoping that we would get some rain recharge on it, and it just hasn’t materialized.”
Andrews said the reduced precipitation makes it that much more important to strive for balance between the operating pools in both lakes.
“I would rather entertain taste and odor complaints in February than having to message water restriction because we don’t have enough water in the lakes in June,” he said.
