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Sewage spills into Lake Washington due to clogged line on Mercer Island's south end
Once again, a serious “grit buildup” has clogged a South-end sewage line, causing a few thousand gallons of sewage to spill into Lake Washington. City workers spent hours on Saturday and Sunday working to unclog the pipeline. It is the second clog to overflow this sewage line in two months.
The exact cause of the sewage-pipe backup is unknown, however a big contributor is when residents dump cooking fats, oils and greases down the drain. Indeed, this was part of the case in both last weekend's clog and the Nov. 14 overflow, according to City Communications Coordinator Joy Johnston.
The city wants to remind the public to please refrain from dumping cooking fats, oils and other greasy substances down kitchen drains.
“As soon as hot water with fats, oils and grease hits cold water, it coagulates. The grease adheres to other grease and gets bigger until it obstructs the pipe — just like a clogged artery,” City Maintenance Director Glenn Boettcher told the Reporter earlier this year.
The city also wants to remind waterfront owners to purchase backwater valves for in order to prevent sewage overflow such as last weekends from surcharging into their home plumbing systems. If a resident is unsure whether he already has a back-flow device, he can always call a plumber to find out.
For more information, call Joy Johnston at 275-7791.