Steve Hall, utility operator at the Kaw River Water Treatment Plant, makes his rounds in this August 2010 file photo, collecting samples of water from the basins at the plant. Many Lawrence residents at the time complained about their water tasting and smelling musty. Officials at the plant attributed the problem to byproducts of algae.

Your tongue isn’t playing a dirty trick on you. Lawrence’s drinking water really does taste odd.

City officials Thursday said Lawrence’s tap water is perfectly safe to drink, despite a strong earthy or musty taste and odor.

For that, you have algae to thank.

Crews at both of the city’s water treatment plants were battling elevated levels of blue-green algae in Clinton Lake and the Kansas River.

“It is not harmful to anybody,” said Jeanette Klamm, projects manager for the city’s utilities department. “You can drink the water. It is strictly an aesthetics thing, but it is an issue.”

City offices received dozens of complaints from across the city about the odd tasting water. Thus far, city leaders don’t have a firm answer on when the water will begin tasting normal again.

“We believe it will be several days or longer,” Klamm said, “but I don’t know that we have a good feel for that right now.”

The city has dealt with the algae issue before — including last summer — but Klamm said this bout has been tougher to deal with because the Kansas River also has high levels of algae. Previously, the algae outbreaks have been confined to Clinton Lake.

This summer has been a prime season for algae growth, said Andy Ziegler, the Kansas water quality specialist for the U.S. Geological Survey. Ziegler said rains early in the summer washed large amounts of nutrients into area lakes. Then the weather became dry and hot, creating the type of warm, clear waters that promote algae growth.

Ziegler, who is based out of the Lawrence USGS office, said the problem may become more prevalent in future years as area lakes become shallower due to siltation.

“There’s a lot about this that we still don’t know,” Ziegler said. “It is an emerging research issue, and an important one because of potential environmental impacts and human health impacts.”

Ziegler said he does agree with the city’s assessment that the odd tasting water is safe to drink. But that’s because it has gone through all the city’s treatment processes. He said there is evidence that people who come in contact with blue-green algae at the lake or in other untreated circumstances can become sick.

Klamm said city crews are working to remove the taste issue by adding more carbon to the city’s treatment process. That has helped some, but has not eliminated all the taste issues. Thus far, the Clinton Treatment Plant has been more effective in removing the taste. The city has begun to shift more of its water production to the Clinton plant and away from the Kaw Water Treatment Plant.

“We’re definitely doing everything we can to address it,” Klamm said.

The problem also naturally will decline over time as this year’s crop of algae dies off and fades away.