Drainage (plumbing) systems

(a) Drainage systems that have openings below the base flood elevation shall be provided with an automatic backwater valve installed in each discharge line passing through a building exterior wall, except backwater valves may be deleted if the fixture drainage openings are located at or above a floor level which is above the surrounding ground level. (b) Drainage systems for emergency servicing facilities that are required to remain in operation during a flood shall be provided with a sealed holding tank and the necessary isolation and diversion piping and appurtenances to withhold or postpone sewage discharge to the sewer system during the flood. The holding tank shall be sized for storage of at least one hundred fifty percent of the anticipated demand for a twenty-four hour period. Vents provided for such holding tank shall terminate at an elevation of at least one foot above the base flood elevation. (c) All pipes in a plumbing vent system shall terminate at an elevation of at least one foot above the base flood elevation. (d) All pipe openings through exterior walls below the base flood elevation shall be floodproofed to prevent infiltration of flood water through spaces between pipes and wall construction materials by use of embedded collars, sleeves, waterstops, or other means as may be approved by the authority having jurisdiction. (2020, ord 20-61, sec 6.) 5F-3-3