Impervious surface, buffers and flood mapping
Concrete work adds impervious surface, which is where city stormwater and floodplain guidance actually bites. New driveways, patios and pads can run into stream-buffer restrictions and lot coverage limits that have nothing to do with the pour itself. Placing fill inside a mapped floodplain is separately regulated. These are siting questions, and they are cheaper to answer before a design than after a permit is refused.
Official sources
Check the parcel's buffers and coverage before design
Citywide mapping will not tell you where a stream buffer crosses your lot, how much impervious surface you already have, or whether your subgrade will hold a slab. Establish the first two with the city and the third with whoever is pouring, before anything is scheduled.
These sources were checked June 20, 2026; rules and maps change.