Can I subdivide my lot? Statewide law first, local zoning next.

Depends entirely on the state and the local code. Three states — California (SB 9), Oregon (HB 2001), and Washington (HB 1110) — have statewide laws that pre-empt local single-family zoning and permit lot splits or middle-housing conversions by right. Every other state defers to the local zoning ordinance, where minimum lot size, corner-lot rules, and frontage requirements govern whether a split is permitted at all. Buildability reads the specific ordinance for your parcel and gives you a preliminary answer in about 20 seconds.

SB 9 (2021) requires California cities to ministerially approve, without hearing, both (a) a lot split of a qualifying single-family parcel into two, and (b) a duplex on each resulting lot — for a maximum of four units where one home stood. Qualifying lots are at least 2,400 sq ft; resulting lots are at least 1,200 sq ft each. The owner must occupy one of the units for three years. Cities have added local ordinances imposing objective standards; the ministerial approval right is state law and cannot be waived.

In pre-emption states, a straightforward SB 9 or HB 2001 split runs $5,000–$25,000: survey, tentative map, plan preparation, filing fees, and civil engineering. Add $10,000–$50,000 for site work (utility separation, driveway, meters) before you build anything. Outside pre-emption states, the range is wider — a full subdivision map through a discretionary hearing can run $30,000–$150,000+, with 6–18 months of process before you're back to the same starting point.

In California under SB 9: 60 days by statute for ministerial approval, though local review can add 30–60 days for objective-standards checks. Oregon and Washington under their pre-emption laws: typically 30–90 days for permit issuance. Elsewhere, discretionary subdivision approval runs 4–12 months and can be longer if hearings are contested. The report shows the local ordinance's timeline provisions where they exist.

In pre-emption states (CA, OR, WA), approval odds are essentially 100% if you meet the objective standards — the whole point of the statutes is to remove discretion. Elsewhere, approval depends on the ordinance and the review body. Cities with a Planning Commission recommendation and Council vote are the highest-risk path; cities with staff-level administrative subdivision are the fastest and most predictable. Buildability's report includes the local review path in the score.

Almost always yes. California SB 9 requires ≥2,400 sq ft and resulting lots ≥1,200 sq ft. Oregon HB 2001 preserves local minimum lot size for the parent parcel. Everywhere else, local zoning specifies minimum lot area, minimum frontage (typically 40–75 feet), and often minimum depth. The Buildability report reads these specific numbers for your parcel.

In pre-emption states, no — you can retain both lots and build on each yourself. Some local ordinances impose owner-occupancy requirements (SB 9 requires three years on one resulting unit), but the underlying property split does not force a sale. Financing is easier when both lots have clear title separately, which is one reason many owners record the split even without immediately building.

Corner lots often have separate front-setback rules on both frontages, which can eliminate a split even where the overall square footage would qualify. Flag lots, panhandle lots, and lots with easements running through them have additional constraints the standard rules miss. The full report reads these against the specific parcel geometry — the free zoning check does not.

Yes — all 50 states. Local zoning is queried live at run time, and the three statewide pre-emption laws are baked into the score. No geographic gaps.