ADU Surveys in Walnut Creek, CA

Walnut Creek's ADU submittal bulletin wants a plot plan that goes further than most homeowners expect: property lines defining the parcel, setbacks, all easements, and all trees with their driplines — explicitly including trees on adjacent property whose driplines reach over your lot. Add any private septic system with its leach-field routing on the semi-rural edges, and the "simple site plan" has become a genuine mapping exercise. The bulletin also requires accurate grade slopes shown on all elevations and building cross-sections, and it draws a hard geotechnical line: a foundation and soils report is required when the site slopes steeper than 1-vertical-to-3-horizontal (roughly 33 percent) or the site has a history of soil-related problems — creep, settlement, lateral spreading — which describes plenty of ground along the Lime Ridge and Shell Ridge edges and the older slopes above Ygnacio Valley.

Most Walnut Creek ADUs go into the backyards of postwar ranch neighborhoods — Northgate, Larkey Park, Saranap borders — where lots are generous but the state's 4-foot setbacks still get used to preserve yard space, and where sixty-year-old fences track the true lines loosely. Our laser-scanned site survey establishes the boundary from monument evidence, captures every structure, tree canopy, and grade break in one visit, and delivers a stamped base map with the easement and dripline content the bulletin asks for, plus staked corners for design and construction. Where slopes approach the geotech threshold, the same scan quantifies them, so you know before submitting whether a soils report is in your future.

Walnut Creek runs a pre-reviewed ADU plan program and even an amnesty program for unpermitted units — both of which still need site-specific plans on accurate base data. Records run through the Contra Costa County Recorder in Martinez; for terrain-heavy parcels see our Walnut Creek topographic surveys.