All buildings with basements, floors, rooms or occupancy areas below ground level at the building site, and served by a public or private sewer system, undergoing substantial improvement as described in this Code, shall have overhead plumbing, a backwater valve system on the exterior service line or another form of flood mitigation as approved by plumbing and local code.
(Ord. passed 3-6-1972; Ord. 93-40, passed 7-27-1993; Ord. 20-23, passed 4-14-2020)