Subsoil drains must discharge into a sump or receiving tank, the contents of which must be lifted and discharged into the drainage system above the cellar floor by some approved method. When directly sewer connected, they must be cut off from the rest of the plumbing system by a brass flap-valve on the inlet to the catch-basin, and the trap on the drain from the catch-basin must be water supplied, as required for cellar drain.