High summer temps cause water odor, taste changes

Arvada residents may have noticed a funny smell or taste to their water recently, but there is no reason to be alarmed.

Because of the extreme heat this summer, several kinds of algae, specifically ceratium and gomphosphaeria, have sprouted in Arvada Reservoir.

“It’s the extended period of it that’s causing it to grow,” said Wendy Forbes, communications manager for the city of Arvada. “There is not enough fluctuation in temperatures.”

As the algae dies, it releases into the water a harmless chemical that causes the change in smell and taste, Forbes said.

Though some residents have tasted and smelled the algae’s effects in their water, Forbes said, it is completely harmless.

“Arvada Water is adding carbons to the system to help with some of that,” she said. “It should stop once the algae is gone.”

It takes about four days for water to pass through the purification system completely, so it takes about that long to collect enough data to see if the extra carbon is helping.

“It takes time for the water to cycle through to see how their chemical balance is affecting the water,” Forbes said.

Residents do not need to take extra precautions when drinking or using water, but there are ways people can reduce the different smell and taste.

“People have different sensitivities; some might be able to smell it or taste it more distinctly than others,” Forbes said. “If they’re noticing the taste or odor, they can refrigerate their water because the colder it is, the less obvious it is, and they can use carbon filters themselves at home. But there is nothing they need to do safetywise.”

The odor was detected around Aug. 6 by Arvada Water officials and carbon has been added since.

Arvada Reservoir is the only reservoir affected by the algae; Ralston Reservoir has not seen the blooms. Forbes said this is because Arvada Reservoir is shallower and therefore the water gets much warmer, and it has a longer detention time.

Officials are monitoring Ralston Reservoir for algae growth.

This is not the first time algae has bloomed at Arvada Reservoir. Arvada Water saw similar blooms in the reservoir in 2003 and 2004.