King County Proposes 12.75% Sewer Rate Increase for 2027, Warns of Future Double-Digit Hikes

King County wastewater officials announced a proposed 12.75% sewer rate increase for 2027 and warned Bellevue residents to expect a series of double-digit rate increases of 12-13% annually in coming years.

Cameron Gro, director of King County's Wastewater Treatment Division, said the proposed rate increase represents a significant departure from historical patterns. "Past rate increases have been more gradual and usually smaller, and they're tied to smaller cost drivers. This year, we're forecasting the start of a series of double-digit rate increases, 12 or 13% per year," Gro said during a utilities discussion.

The increases are driven by three primary factors: regulatory requirements, aging infrastructure replacement, and capacity expansion for population growth. About half of King County's projected $7 billion capital program over the next decade is needed to comply with state and federal regulations.

"Much of our regional wastewater system has been operating reliably each day since it was built in the 1960s, but some pieces of that infrastructure are nearing the end of their service life," Gro explained. He noted that equipment has deteriorated to the point where "we can't even find replacement parts on the marketplace."

The rate increases will directly impact Bellevue residents, as the city represents King County's wholesale monthly sewer rate as a pass-through charge on customer bills, typically shown as a "King County Treatment Charge" line item.

King County's wastewater utility is funded almost entirely by ratepayers, with no support from general county taxes. The utility serves nearly 2 million people, including all Bellevue residents.

To address affordability concerns, King County Executive Dow Constantine has directed the utility to engage with local, state, and federal partners to create "a path towards a more financially sustainable future." The county is also working to improve rate predictability and transparency, including incorporating affordability metrics into planning processes and evaluating rate relief approaches for lower-income customers.

"We're working every day to reduce ratepayer costs and we're successfully competing for lower interest loans and loan flexibility offered by state and federal agencies," Gro said.

Some lower-priority projects have already been deferred, but Gro indicated that major regulatory compliance work cannot be postponed, as the county must complete combined sewer overflow reduction projects by 2037 under a federal consent decree.

Watch the discussion: