EVERETT — The city of Everett’s program to install flood-prevention devices in the city’s north end has gotten off to a slow start.

In 2013, sudden severe storms Aug. 29 and Sept. 6 caused scores of homes and businesses in Everett’s older neighborhoods to be flooded.

This year the city enacted a program to install backwater valves in 1,800 of the most vulnerable buildings to prevent that from happening again.

But only 15 of the devices were installed the first six weeks of the city’s program, said Grant Moen, a senior engineer in the city’s Public Works department.

The valves prevent water from moving up a pipe and into a house, and is the city’s immediate solution to its flood-prone sewer-stormwater system problem.

The city has offered to pay up to $2,500 per house in a rebate program to get residents to install the devices.

Approximately another 50 valves will be installed in the next few months, Moen said, and about 600 residents have sent in information about their basements, the first stage in applying for the rebate.

“As far as actually getting the backwater valves in the ground, that’s still ramping up,” Moen said.

The city has estimated it will ultimately pay out $4.3 million in claims stemming from the 2013 flooding.

The valve program was intended to prevent the worst of the flooding as well as the claims for a total cost of about $4.5 million.

The real culprit in the flooding, however, was the city’s antiquated combined sewer and stormwater system. Separating 145 miles of sewer and stormwater pipe in the north end of the city could cost up to $1 billion and take 30 years to complete.

City officials hope the rebate will encourage homeowners to undertake the work — the city may later install valves in public rights-of-way, but that might take several years to finish.

The city has provided another incentive for homeowners as well: capping all future claims from flooding at $25,000 per building.

After June 1, 2015, Everett also will not settle any claims from those 1,800 homes it has identified.

Part of the reason why the program has been slow to start may be because the homeowners have to coordinate the work with an approved contractor from a list of 20 the city has published.

The city is also requiring homeowners to fill out a W-9 form, because the rebate from the city might be taxable under federal law. The city is waiting to hear back from the IRS for a clarification, Moen said.

Contractors’ schedules are already filling up.

Cindi Rice, co-owner of Everett-based American Septic and Side Sewer LLC, said she’s been getting calls every day.

“We’re booked up all next month and we did quite a few this month,” Rice said.

The city also has removed about 100 homes from the list of 1,800 that require a valve, mostly because the house’s basement is higher in elevation than the local sewer manhole.

In other cases, a home might not have any plumbing in the basement, or has a grinder pump installed that can function as a backwater device, Moen said.

Residents usually pay the contractors outright and then get a rebate, but some contractors, such as American Septic, have offered to bill the city directly.

Initially those payments took up to two weeks to be received.

“They’ve since improved it and we’re now trying to getting paid in a week,” Rice said.

“It’s been a little difficult, a little stressful, but somehow we’ve been making it through,” she said.

Chris Winters: 425-374-4165; cwinters@heraldnet.com. Twitter: @Chris_At_Herald.