The City of Ashland reported that 500 gallons of backwash spilled from the water treatment plant on Granite Street into Ashland Creek and the swimming hole in Lithia Park.
At about 2 p.m. the backwash, which comes from filters being cleaned, bubbled up through a manhole on the dirt access road connecting the water treatment plant to Granite Street and spilled into Ashland Creek above the swimming hole. Filter backwash from the water treatment plant is piped via a sewer line to the waste water treatment plant, officials said.
This backwash water typically has no biological contamination and is not hazardous to humans, officials said. It contains sediment and alum, a chemical used to clean raw water.
The disposal of the backwash was halted while city crews cleared the plugged line.
"The line was plugged by excess sediment which caused the filter backwash to back up in the manhole," Pieter Smeenk, engineer for the City of Ashland, said in a prepared statement.
He said crews cleaned away the clogging sediment.
The city is testing water quality in the creek and the swimming hole. Signs will be posted at the swimming hole and other points of access to Ashland Creek to alert the public about the spill until tests confirm the water is safe.