Issaquah committee backs staff plan to align duplex and single-family water and sewer rates; King County sewer minimum to be recalibrated

The Issaquah Mobility and Infrastructure Committee on July 15 reviewed a utility rate study and indicated support for staff recommendations to align duplex and single-family bimonthly rates for water and sewer, recalibrate the minimum sewer-volume assumption to match King County’s Residential Customer Equivalent (RCE) of 15 CCF, and continue the current stormwater rate structure.

The study, presented by city staff member Matt and consultant Sergei, updates a 2020 comprehensive rate study and covers rate-setting steps for water, sewer and stormwater for the next five years. Sergei summarized the three-step process as "revenue requirement, cost of service, and rate design" and said that "there's not a 1 size fits all solution" when deciding how much to recover through fixed versus variable charges.

Why it matters: the committee is setting policy direction now so staff can present a final summary and formal rate adoption later this year. The city plans a summary presentation to the Mobility and Infrastructure Committee on Sept. 16 and aims to adopt the rate ordinance at the Oct. 20 regular council meeting; if adopted, changes would be implemented beginning in 2026.

What the committee reviewed and recommended

- Align duplex with single-family rates (water and sewer): Staff proposed consolidating duplex billing into the single-family rate schedule for both fixed and volume structures starting in 2026. Sergei said duplexes and single-family homes have "fairly…