SOUTH LAKE TAHOE, Calif. — A strong odor emanating from the Black Bart Avenue area of South Lake Tahoe is due to the local utility district rehabilitating an over 50-year old clarifier and storing about two million gallons of partially treated wastewater in the emergency retention basin, officials announced Monday.

The combination of high flows due to increased visitation over the Fourth of July weekend, unusually high temperatures in the valley, and a settling problem with the remaining two secondary clarifiers caused the South Tahoe Public Utility District to temporarily store the partially treated water, but officials say the wastewater treatment plant has stabilized and the district is returning the water and conducting cleaning operations.

“We don’t take this lightly and only use the emergency retention basins as a last resort,” said Jeff Lee, manager of plant operations. “We thank our neighbors for their understanding and patience and are doing everything we can to remedy the situation as quickly as possible.”

The district maintains two emergency retention basins which are designed to store 56 million gallons of water when there is an issue at the treatment plant. The district last used the basins to store partially treated wastewater during the big winter storms of February 2017. Prior to that, the basins had not been used for this purpose since 1997, said a press release.

When the wastewater treatment plant was built in the 1950s, it was located on the outskirts of town. Over the last 70 years, South Lake Tahoe has grown and the plant is now located right in the heart of town.

“The District is very conscientious of odors and has invested in various measures over the years to reduce them,” Lee said. “The reality is that we can’t totally remove odors, but we continue to monitor odor on a daily basis and run our operations to minimize impacts to our neighbors.”

For more information, visit stpud.us.