Sammamish Planning Commission reviews proposed square‑foot impact‑fee formula, hears questions on affordability and data

Sammamish Planning Commission members heard a staff presentation Sept. 10 on proposed changes to the city’s impact‑fee system that would scale transportation and parks fees by unit square footage, and they received public comments questioning the underlying traffic and housing data and the effect of fee waivers on city revenues.

The proposal — presented by city staff members Evan and David — follows Senate Bill 5258 (2023), which requires jurisdictions planning under the Growth Management Act to scale impact fees by unit characteristics such as square footage, bedrooms or trip generation. "Impact fees are a one‑time fee assessed on new development," Evan said during the presentation, and the staff recommended square footage as the easiest and most objective scaling measure to administer.

Commissioners and residents pressed staff on the data and legal defensibility behind the proposed minimum and maximum fee caps. Resident Richard Johnson questioned the traffic analysis referenced in the environmental review, arguing the model used inconsistent commercial‑square‑foot inputs and altered trip‑generation assumptions; he told the commission, "the traffic numbers are probably wrong." Resident Cheryl Wagner asked, "Where is the affordable housing?" and said, "Sammamish is required by the state to plan for and accommodate 1,550 units of extremely low income housing," urging staff to show how the town‑center proposals meet that need.

Why it matters: the city has not updated its impact fees in about 10 years, and the chosen scaling method will change the per‑unit fee paid by smaller units (which state lawmakers wanted to protect) and by very large homes. Staff said the change is intended to make fees proportionate to the estimated public‑service impact of new residents and to align fee collection with the comprehensive plan’s adopted levels of service.

How the proposed formula would work: staff and their consultant (FCS) showed a hypothetical example — "Marksburg" — to illustrate the calculations. Transportation fees are derived by dividing the cost of capacity‑increasing transportation projects by the forecasted PM peak trip ends generated by new housing; staff’s example produced a $15,000 transportation fee. Parks fees use a different construct: staff calculate parks inventory value per person, estimate the parks value needed for anticipated population growth and then apply a capacity adjustment based on the projects planned to serve growth; the example produced a $5,000 parks fee. To scale fees, staff proposed setting a minimum amount pegged to very small units (set by estimated occupants) and a maximum pegged where occupancy per unit plateaus in their occupancy‑by‑square‑foot data; anything between would scale by square foot.

Key concerns raised in the meeting - Data and model inputs: Commenters and commissioners asked staff to explain and justify trip‑generation inputs and the consultant’s occupancy curve (staff cited U.S. Census regional data and noted the consultant will use local Sammamish values). Several commissioners questioned an occupancy curve captioned “Seattle Metro Area 2021,” saying it did not match local experience; one commissioner said, "I don't care what the data says. That's not Sammamish." Staff said FCS will present the local inputs and that the city can supply additional local datasets (for example, school‑district student generation reports) to help refine assumptions. - Legal defensibility of caps and scaling: Commissioners asked how the city would defend any chosen maximum fee amount in the event of a proportionality challenge. David, a city staff member, summarized the legal constraint bluntly: "It's not defensible," when describing unlimited, uncapped square‑foot scaling without data to show additional occupancy or trip impacts for extremely large homes. Commissioners requested a briefing from the city attorney and expected the consultant to address nexus and proportionality at the next presentation. - Affordable housing and waivers: Staff noted the city’s existing code already includes an 80% impact‑fee reduction for units restricted to 80% area‑median income (AMI) and that the council recently adopted a $34.45 per square‑foot in‑lieu affordable‑housing fee. Commissioners and members of the public debated whether additional waivers or discounts are useful. Staff cautioned that if the city waives fees for affordable units, the revenue shortfall must be covered from other public funds; staff provided a hypothetical showing substantial long‑term revenue loss if large portions of growth received reduced fees. Commissioners generally favored relying on the square‑foot scaling to lower fees for smaller units and treating deeper affordable housing (very low AMI) as a case for explicit public subsidy or partnership rather than broad fee waivers. - Parks versus transportation methodologies: Commissioners asked why parks fees begin from the current parks inventory value per person whereas transportation fees are derived from a project list that includes unconstrained long‑term improvements. Staff said the two fee types are built differently and asked the consultant to explain the rationale at the November session. - Timing and frequency of updates: Staff proposed updating fees every two years (off the city’s biennial budget adoption) and codifying a formula and process for predictability. Several commissioners suggested longer intervals (for example, five years) or tying updates to updates of relevant planning or capital documents (the TIP, TMP or the parks plan).

Quotes from meeting participants are included only when the speaker is identified in the transcript. In addition to the quotes above, David (city staff member) told commissioners that the county school‑fee process uses bedroom counts and that the city had avoided bedroom‑based scaling because bedrooms are harder to measure objectively at permitting.

Next steps: FCS, the consultant, will present the detailed calculations and local inputs at a Nov. 6 meeting; staff said they will return with draft fee amounts, examples comparing current and proposed fees, and answers to commissioners’ requests — including legal guidance on defensibility, clarification on parks versus transportation methodology, and an estimate of the revenue impact of any proposed discount or waiver policies. Commissioners asked staff to supply comparison examples, school‑district student‑generation data, and to invite the city attorney to discuss nexus and proportionality.

Ending: The Planning Commission continued the discussion toward a Nov. 6 follow‑up where the consultant will present specific fee tables and legal staff will be asked to brief commissioners on defensibility and case law.