Urban Acupuncture is a feasibility tool. For any residential lot in Seattle it estimates which middle-housing forms physically fit under current zoning, draws the buildable area, and models rough economics. It is built on open civic data and is free to use.

It is not a permit, an appraisal, an offer, or professional architectural or legal advice. Everything it shows is screened from public data and modeled — useful for a first look and a conversation, not a substitute for a licensed contractor, an architect, and the Seattle Department of Construction & Inspections (SDCI).

Property sales are used only to flag recent activity; no buyer or seller names are ingested or shown. Owner identities are never displayed.

On top of the geometry, each lot is enriched with the factors a real decision needs: distance to major transit, environmentally critical areas, alley access, tree canopy, and sewer-capacity risk.

Each standard plan has explicit, published criteria: hard filters a lot must pass (zoning, lot size and shape, access, environmental constraints), plus verification flags that note what still needs field confirmation. A lot that clears the filters is a screened candidate for that plan — never a finished answer.

Examples in the current catalog include a low-cost backyard cottage, a big-house conversion into flats, and keeper-house-plus-rear-homes patterns. The catalog grows as new patterns are researched and modeled.

Construction costs, rents, and sale prices are modeled from source-labeled public inputs and explicit planning assumptions. Standard plans use a maintained economics workbook as their baseline. Figures are presented as low/base/high ranges to show sensitivity, but a wide range is not a substitute for a bid.

Rent sources are resolved by type and geography. An approved bedroom-specific observed source would rank first. HUD Small Area Fair Market Rent is currently the primary ZIP-level screening basis; it is not observed market rent or necessarily the local housing authority payment standard. Census ACS table B25031 is a lower-confidence fallback and QA benchmark: it reports lagging median gross rent for occupied units paying cash rent by ZIP Code Tabulation Area, and ZCTAs do not exactly equal USPS ZIPs.

Most owners don't pay cash. Owner-occupied mortgages let a household finance a 2–4 unit home — or build a new unit — with a low down payment: roughly 3.5% with an FHA loan or 5% with a conventional Fannie Mae loan, on up to four units. Renovation and construction loans (FHA 203(k), Fannie Mae HomeStyle, Freddie Mac CHOICERenovation) extend the same low-down treatment to building a backyard cottage or converting a house, underwriting against the finished value.

The practical effect is that adding a home can be within reach of a moderate-income owner-occupant, not only a cash investor — and the rent from the added unit can offset much of the mortgage. Washington down-payment assistance (the Covenant Homeownership Program, WSHFC programs) can stack on top for eligible buyers.

If a parcel fact, source date, rule, or modeled result appears wrong, send the parcel ID, the claim shown, the source or value you believe should replace it, and any supporting public record to [email protected]. Submitted corrections are reviewed as evidence; they do not silently overwrite source records or historical model versions.

• ·Buildable envelopes, costs, and income are modeled estimates; construction-cost ranges are currently unverified planning assumptions and individual sites vary widely.
• ·A fit on the map does not mean a project is permittable; site conditions, utilities, trees, and review can change the outcome.
• ·Nothing here is investment, legal, lending, or architectural advice.
• ·Always consult a licensed contractor, the relevant professionals, and SDCI before making financial or design decisions.

This is a living document. As data sources, screening rules, and the cost model improve, we update this page and note the change with a new version and date. If a number or method in the tool surprises you, this page should explain why — and if it doesn't, that's a gap worth telling us about.