King County sewer project failed soon after installation, costing millions to fix

SEATTLE — The bill is rising for utility ratepayers in King County after a pipe in a pollution-prevention project broke months after it went online.

This spring, crews completed replacing the pipe beneath Seattle's Magnolia neighborhood through a risky procedure called pipe bursting.

The previous pipe failed in 2016, months after the combined sewer overflow project was completed.

When rainstorms overwhelm sewers, untreated wastewater goes right into Puget Sound.

The South Magnolia CSO project is intended to collect that wastewater, send it through a half-mile pipe beneath the bluff and into a 1.5 million gallon holding tank at Smith Cove.

When the storm passes, sewage and storm water is released to the treatment plant.

The project cost $11 million, paid through utility bills.

It started operating in December 2015 and worked for a few months.

Then, on Sept. 19, 2016, Seattle got a big rainstorm, and the new system failed.

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"We noticed something was wrong because the tank was not getting the flows that we predicted," said Bruce Kessler, assistant director of King County's Wastewater Treatment Division.

KIRO 7 filed a records request to obtain videos from robotic cameras sent to inspect the 30-inch pipe.

Rocks and silt blocked the way.

The robot was never able to reach the break, but county officials estimated the debris field stretched 500 feet.

"There obviously had to be a hole in the pipe somewhere and surrounding soils were getting into the pipeline," Kessler said.

Walsh Group installed the pipe that failed, and the county hired the same contractor to replace it.

"Is the county doubling down on a bad decision of some kind?" asked Elizabeth Campbell, a Magnolia neighborhood activist with a lot of questions about the CSO project.

"Why did it break in the first place?" Campbell asked.

Kessler told KIRO 7 the cause of the break is unclear, but there's no sign the pipe was incorrectly installed.

He says possibilities include the pipe was somehow overstressed.

KIRO 7 reviewed county bid documents that gave contractors the option of choosing between using two types of piping, high density polyethylene and what's called fusible PVC.

Walsh installed FPVC, a first for King County.

In the repair, crews replaced the FPVC with the other option, HDPE, following a risky and expensive process known as pipe bursting.

Of the total original project cost of $11 million, King County says $9.5 million was for installing the pipe that failed.

As of March 2018, King County spent $7.7 million fixing the pipe.

The county secured $17 million from utility ratepayers for the repair, but doesn't expect to spend it all.

There is a $26.4 million dollar insurance policy on the project, but it's not yet clear how much ratepayer money might be recovered.

"Here you have a doubling of a project cost, you have this spontaneous break with no real answer about how it happened," Campbell said.

County officials say they went with the same contractor for the fix because switching to a new company would have delayed the project at least a year.

Sewer overflows into Puget Sound are governed by a federal consent decree, which means the county could finally be in compliance when the connections to the new pipe are done by the end of this year.