Faced with a sewer system that is nearing the end of its useful life, the Mountlake Terrace City Council learned during its March 14 work/study session that an increase in sewer rates will be necessary. The question now is, how much rates will go up and how quickly.

The sewer rate discussion followed a Comprehensive Sewer System Plan Update, delivered by Stacy Clear from Gray and Osborne Engineers. The goal, she said, was to provide a guide for how the city can address both its current and future sewer system needs. The report will be submitted to both the Washington State Departments of Health and Ecology for their review.

The update presented March 14 evaluated the city’s existing system and assessed the city’s operations and maintenance abilities, and was followed by recommendations on how to pay for improvements.

“A lot of the sewer lines within the city are old. They were installed within the 1950s, they are concrete pipes. They really nearing the end of their aging lifespan,” Clear said. Some of the sewer lines are undersized, meaning they aren’t designed to handle existing flows and also won’t be able to accommodate future growth, she added.

There are also issues with inflow and infiltration, meaning that clean water is seeping into the sewage system, causing an increase in overall flows. This increases the city’s costs in two ways: First, the City of Mountlake Terrace sends its sewage to the City of Edmonds wastewater treatment plant, and the city pays Edmonds for sewage treatment under a long-term interlocal agreement. More flows mean greater costs, Clear said. In addition, more flows due to clean water entering the system requires larger pipes, which also increases costs.

“We’re recommending about five miles of specific pipe replacements,” Clear said. “Some of these are just due to them (the pipes) being undersized, some of them are due to this I and I (inflow and infiltration) problem.

The report, which covers system needs from now through 2035, recommends the City of Mountlake Terrace allocates funds every year for pipe replacement. In addition to future rate increases, it recommends bond financing as well as development of capital reserves for future needs.

Another major cost facing Moutlake Terrace is helping to fund planned upgrades to the  Edmonds treatment plant. Edmonds is planning to replace its aging sludge incinerator with a $16 million system that includes a two-step process that involves sludge drying and pyrolysis – the chemical decomposition of organic materials at high heat with little to no oxygen.

There is also a recommendation to increase Mountlake Terrace staffing for operations and maintenance work on its system, which includes 74 miles of sewer pipes in its 2,400-acre service area, plus 1,500 manholes and four lift stations. “To provide adequate service for a system of this size, you really should have four full-time staff and unfortunately the city only has two full-time staff,” Clear said.

Without increased staff, the city will be forced to continue its practice of deferring ongoing  maintenance, which accelerates the aging of sewer system infrastructure, Clear said.

Following Clear’s presentation, the council heard from consultant FCS Group on a proposed plan to pay for the improvements. The plan included a 55 percent increase in sewer rates starting in 2020, resulting in an average rate hike from the current $34 per month to just under $53 a month. Smaller annual increases would follow.

Councilmembers expressed their collective concerns about the possibility of a sewer rate increase, noting that some citizens are already upset over a nearly $22-per-month average increase in water rates, which took effect in January.

“How do we know this isn’t a gold-plated plan?” asked Councilmember Bryan Wahl.

Public Works Operations Manager Peter Dressel said that the plan represents “a very minimalistic approach to the fact that our system is 60 to 70 years old.” During heavy rain, some of the city’s sewer pipes “are at their capacity,” Dressel said. Not upgrading the existing system could future pipe failures, which would be very expensive to fix, he added.

Paying the city’s share of the Edmonds treatment plant upgrade — Mountlake Terrace is on the hook for covering 23 percent of the estimated $16 million cost — is also a factor in increasing sewage system costs, he said.

Wahl said that while he agrees the city needs to upgrade its infrastructure, he is hesitant to approve any rate increase due to the added burden on taxpayers already facing increased taxes at the local, county and state level. “We have thrown the kitchen sink at the taxpayer and our customers,” Wahl said. “And we are expecting them to suck it up. And they can’t.”

Wahl and other councilmembers pressed the consultants and city staff to take another look at restructuring the proposal to make it more affordable.

“I guess I want options right now, instead of saying yes or no,” Wahl said.

“It’s kind of the good, the bad and the ugly,” added Mayor Pro Tem Doug McCardle. “The good is, we have a sewer system that’s working. The bad is, it was put in the ’50s and ’60s and is starting to fail. The ugly is, how do we pay for it?”

Dressler noted that some costs are fixed, such those related to the Edmonds treatment plant. Rates also need to be high enough to ensure the city can acquire bonding, which will also be required in addition to rate hikes, to fund future improvements. One thing the city can revisit, he said, is whether it’s possible to delay work on some of the line replacements so that the rate increases are more gradual — both initially and over time.

City Manager Scott Hugill noted that council’s main task is to review and approve the current sewer comprehensive plan at Monday night’s March 18 business meeting so the city can submit it to the Washington State Departments of Health and Ecology for review.

Following state approval, the city will need to conduct an official sewer rate study and will talk more about rates at the end of 2019, Hugill said. “That will give us time to vet through those options and come back with ‘can we stagger the projects more? Are there other option out there?'”

Monday night’s council meeting will begin at 7 p.m. in. interim Mountlake Terrace City Hall
6100 219th St. SW, 2nd Floor. You can see the complete agenda here.