Does your water taste weird? Or smell funny? This might be why, Manatee County says

A summer bloom of blue-green algae in the Lake Manatee Reservoir could be making your water smell or taste bad, Manatee County Government said in a news release Monday.

Customers of Manatee County Utilities “may notice a slight earthy/musty taste to their water,” the news release said.

About two-thirds of county-supplied water comes from Lake Manatee, where blooms of blue-green algae sometimes occur.

The county provides water to about 362,000 people through 136,000 service connections, as well as providing wholesale water to Palmetto, Longboat Key and portions of Sarasota County.

Despite any off-putting taste, county officials say that the water remains safe for consumption.

“Current conditions favor a bloom, and tests conducted over the past several weeks indicate the presence of blue-green algae at elevated concentrations,” the news release said. “While the odor or taste may be noticeable, there are no known health effects caused by the presence of these compounds.”

Do I need to treat or boil my water?

Water supplied to Manatee County Utilities customers is safe to drink as-is, according to the county.

Boiling water is not necessary, but customers may choose to use a carbon filter on their faucet or refrigerator water system, or a filtrated pitcher, to reduce any undesirable taste or odor.

The county is also using powdered, activated carbon to treat the water at the reservoir. However, this method does not always remove all of the algal bloom’s impacts when concentrations exceed a certain amount.

Is blue-green algae toxic?

Some blue-green algae species produce toxins that are harmful to humans at elevated levels, while others do not. Manatee County Government did not identify which species of algae is blooming in the reservoir.

However, concentrations are not high enough to impact the safety of the water, the county said. The blooms can give water a musty taste and odor at levels as low as parts per trillion.

“Certain algae and bacteria produce compounds (MIB and geosmin) as part of their metabolism that impart the earthy/musty odor/taste to the water,” the county says on its water quality info page. “These same compounds are produced by bacteria in soil and make dirt smell like dirt.”

“We are monitoring the levels of algae and odorants and treating for them until water quality returns to normal,” Manatee County Utilities Deputy Director Katie Gilmore said in the news release.

How often do blooms happen in Lake Manatee?

Algal blooms in Lake Manatee are a normal occurrence, according to Manatee County.

The blooms occur most often in the late spring or summer, show up an average of two to three times per year and last two to four weeks each, the county says.

Drought conditions make it more difficult for Manatee County Utilities to remove the odor-causing compounds.

This story was originally published July 10, 2023 at 1:23 PM.