ADU Surveys in Petaluma, CA

Petaluma's ADU rules leave a narrow physical margin. The city's ADU and JADU handout puts detached units at a minimum 4-foot side setback and a minimum 4-foot rear setback, and it uses that same 4-foot number as one of the conditions for the exemptions from lot coverage, floor area ratio, and open space that make small units feasible: 800 square feet or less, no taller than 16 feet, minimum 4-foot side and rear yard setbacks, and compliance with other local development standards. An attached ADU may exceed 50 percent of the primary residence's living area only by meeting that same package. ADUs are capped at 1,000 square feet, JADUs at 500, detached height varies by zoning in a range around 20 to 21 feet, units under 750 square feet are exempt from city development impact fees, and the review clock is 60 days.

Four feet is not much room to be wrong about where the line is. Petaluma has no published requirement that a licensed surveyor prepare the site plan, but the universal rules still apply: setbacks are measured from the legal property line, not from a fence somebody built in 1974, and field inspectors frequently require a surveyor to verify foundation forms before the pour. On the west side, lots on the old townsite grid carry generous alleys and decades of accumulated encroachment. On the east side, subdivision monuments usually survive but rarely coincide with the fences. Starting an ADU with a comprehensive survey is cheaper than discovering the problem at inspection.

Our Trimble laser scanner covers the whole site in one visit: boundary corners staked from recovered monuments and record research, existing structures with eaves and projections, hardscape, trees, utilities, and the grades that decide where water goes. Floodplain parcels get NAVD88 elevations in the same pass. Deliverables are a stamped site plan base map and layered DWG. For terrain-driven design, see our Petaluma topographic surveys.