Pride Plumbing came out and replaced a kitchen sink's leaking galvanized under-sink drain assembly, P-trap, and cast-iron drain line through the floor to under the house in the basement, and to where it ties into the main sewer drain stack, with new PVC piping and fittings. Also, underneath the sink, we added an air admittance valve to the new drain line and capped off the old galvanized drain line coming in through the wall.