Interior work, with a threshold to watch
Bathroom work is interior and largely outside flood and wind provisions. The exception is scale: inside a mapped flood zone, work large enough relative to the structure's value can cross the substantial-improvement threshold and pull the whole building into compliance. On slab construction, relocating a fixture also means cutting concrete, which is permitted through Planning and Development Services.
Official sources
Check the threshold before a large renovation
Citywide mapping cannot tell you your parcel's zone, your structure's assessed value, or what is under the slab. Establish the first two with the city if the project is substantial, and the third before anyone cuts.
Research date
Sources reviewed June 22, 2026. External requirements and maps can change.