People living on the west side of Lawrence may have noticed a rather unpleasant change in their tap water this week.

Rayanne Dowell sure did.

“It smells and tastes like dirt,” she said.

She and her family regularly drink the city’s tap water, which she says she loves.

“We just can’t drink this; it’s really foul,” Dowell said. “So I’ve been buying bottled water, but it’s getting expensive.”

Sunshine and nutrients at Clinton Lake have increased algae, which contributes to the “musky” odor and taste lingering in the city’s potable water. The lake is a source of water primarily for areas west of Iowa Street and is treated at Clinton Water Treatment Plant.

“There are people who are very sensitive and pick this up and others who don’t at all,” said Philip Ciesielski, the city’s assistant director of utilities. “It’s very personal down to the sensitivity of a person’s palate.”

Ciesielski said the taste and odor issues hit the Clinton Water Treatment Plant harder than usual this year in part because of the seasonal spike in algae populations and the high demand for water.

In response, the city increased the amount of carbon it puts in the water it treats beginning last weekend when officials noticed a change in water quality. The fix hasn’t been completely successful.

“As unpleasant as it can be, it’s strictly an aesthetic issue,” Ciesielski said. “In all other ways it’s safe to drink.”

Today, a different type of carbon is expected to be delivered to the treatment plant that Ciesielski said has been more effective in eliminating the foul odor and taste.

Paul Liechti, assistant director of the Kansas Biological Survey, said conditions are prime for algae growth. The one-celled organisms produce oxygen during the daylight and die off at night, he said. When they die, they produce higher levels of geosmine, which is what causes the bad taste and odor in potable water.

“Some of the worst conditions are in the fall, when you have the big (algae) die-off,” Liechti said.

The increased summer demand for water translates to higher volumes of water moving faster than usual through the treatment plant, Ciesielski said.

On Tuesday, the city treated 25 million gallons of water, he said. The amount fell to 14 million gallons Wednesday with the rainfall of .77 inches.

“We anticipate that ramping up quickly as it stays hot and dry,” he said.

Ciesielski said when demand is high the city sometimes uses water from the Kaw Water Treatment Plant, which uses the Kansas River as its source. A flowing stream doesn’t have the same algae population that a lake does, he said.