Seattle briefing: MHA’s role and an outside evaluation — consultants urge fee recalibration, faster timing of payments

City planning staff, the mayor’s office and outside consultants briefed the Select Committee on the Comprehensive Plan March 29 on Mandatory Housing Affordability (MHA), how the program would be applied under the proposed 1 Seattle comprehensive plan, and an independent five‑year evaluation of MHA outcomes.

“Mandatory housing affordability” is a city program that requires new development in many multifamily and commercial zones either to include affordable units or to pay an in‑lieu fee that the city uses to fund affordable housing, Jeff Wendland of the Office of Planning and Community Development told the committee. Under current practice, MHA is added when an up‑zone expands development capacity; higher up‑zones generally carry larger MHA requirements.

The executive recommended retaining MHA where the proposed plan creates neighborhood centers, expanded urban and regional centers and frequent‑transit corridors — a change staff said would increase the acreage subject to MHA by about 21 percent — but not applying MHA across the broader neighborhood residential (formerly single‑family) zones. Staff told the committee the rationale for that exception includes two points: first, HB 11‑10 already allows a built‑in density bonus for middle housing in NR zones (for example, up to six units on some lots when at least two are affordable), and second, the city’s consultant work suggests many small parcels in the NR proposal are unlikely to be economically feasible for middle‑housing construction with an additional MHA requirement.

Staff cited an Eco Northwest analysis estimating roughly…