Elevation certificate

An elevation certificate is the surveyed document recording a building's flood-relevant elevations against the datum the flood map uses: lowest floor, lowest adjacent grade, machinery levels, and the rest, certified by a licensed surveyor or engineer. It is the instrument that replaces estimated flood exposure with measured fact — insurers price against it, and floodplain permitting relies on it.

For transactions in and near mapped zones, the certificate is the cheap resolution to expensive uncertainty: screening estimates from mapped elevations and ground data can only approximate what one survey settles. An existing certificate is also a reusable asset that conveys understanding of the building — worth locating in diligence before commissioning anew.