Interior work, with a scale exception
Bathroom work is interior and mostly outside floodplain and stormwater administration. The exception is scale: on a property inside a mapped floodplain, work extensive enough relative to the structure's value can engage additional requirements. Relocating a fixture is separately permit-triggering, and in the older housing stock the drain routing that makes it possible is frequently the real constraint.
Official sources
Check the threshold, then check behind the tile
Citywide records cannot tell you your parcel's flood status, your structure's valuation, or what is behind the tile. Establish the first two if the project is substantial, and the third before demolition rather than after.
When this was checked
Sources were last reviewed June 20, 2026. Requirements and maps change, so confirm anything time-sensitive.