Cal. Gov't Code § 66474.5
(a) Notwithstanding any other law, after the amendments required by Sections 65302.9 and 65860.1 have become effective, the legislative body of each city and county within the Sacramento-San Joaquin Valley shall deny approval of a tentative map, or a parcel map for which a tentative map was not required, for a subdivision that is located within a flood hazard zone unless the city or county finds, based on substantial evidence in the record, one of the following: