City of Philomath public works staff presented an updated methodology for the city’s stormwater system development charges (SDCs) at the Oct. 17 Public Works Committee meeting, and the committee agreed by consensus to advance the methodology to a public hearing 90 days or more from the meeting date.

The methodology update recalculates the SDC to reflect the city’s recently completed stormwater master plan, an updated inventory of existing oversized storm facilities and a 20‑year build‑out projection. Using those inputs, staff said the recommended residential SDC would be $2,965 per equivalent dwelling unit (EDU). That total includes a reimbursement component of $2,202 per EDU for the value of existing oversized infrastructure, an improvement (future investment) component of $734 per EDU and a 1% administrative fee (about $29). The recommended starting numbers were tied to the Engineering News‑Record construction cost index used for other city SDCs.

Why it matters: SDCs are one‑time fees charged to new development to pay its share of existing system replacement and future capacity. Updating this methodology will change the fee new development pays and could affect the cost of housing and commercial projects in Philomath; it also determines which future projects the city can fund from SDC proceeds.

Key points from the presentation and committee discussion:

- Staff said the methodology uses a 20‑year master‑plan horizon and divides the total present value of existing oversized storm infrastructure plus projected improvement costs by the forecasted impervious area (and EDU counts for residential) to derive a per‑square‑foot or per‑EDU charge. Staff reported a calculated existing oversized replacement value of about $7.19 million and anticipated future improvements cost of roughly $2.40 million. Combined with a projected full build‑out impervious area of roughly 9.8 million square feet, staff derived the per‑square‑foot and per‑EDU numbers presented to the committee.

- The committee discussed whether to retain the residential EDU assumption (3,000 square feet of impervious area per dwelling) or to compute fees for all development types directly from measured or permitted impervious area. Several members said charging by actual impervious area for all development (residential, multifamily, commercial, industrial) would be simpler and would avoid hidden cross‑subsidies; staff agreed to revise the draft methodology language to make that alignment and to clarify treatment of multifamily housing (whether to treat multifamily as residential EDUs or as measured impervious area converted to EDU equivalents).

- Staff described required statutory elements and procedures: the methodology provides credit mechanisms for developers who build SDC‑eligible infrastructure, ties annual updates to an index (ENR CCI), and includes appeal procedures that can be taken through the writ‑of‑review process described in Oregon statute (ORS). Staff said they will publish notices to contractors and developers that have done work in the city over the prior two years and set a council hearing date at least 90 days after public notice is issued.

Committee direction and next steps

The committee gave unanimous consensus to approve the methodology with the amendment described above (align residential and nonresidential calculations to per‑square‑foot impervious area or otherwise clarify multifamily treatment), to set a public hearing at least 90 days from notice, and to begin notice to interested parties. Staff said the final numeric values will be refreshed to the index value on the month of implementation so the adopted fee does not begin “behind the curve.”

What was not decided

No final resolution or ordinance was adopted at the committee meeting; the committee set direction to bring a revised methodology and a public hearing to the city council. Staff noted developers may submit project‑specific utility impact analyses to receive adjustments or credits based on actual costs for eligible constructed projects; final credits are calculated on documented, agreed actual costs.

Committee members, staff and others present characterized the update as a needed modernization of a methodology last updated in 1998 and as more defensible and transparent than the prior version. The committee also agreed staff should circulate the revised draft to interested parties and return with a hearing date and an implementation schedule.