1645 Backwater valve
1646 Downspout connection upstream of trap
1647 Flashing problems
1648 Horizontal vent offset
1649 Vent on the wrong side of the trap
1650 Wet venting |  1651 Venting an island sink (if below-floor trap not permitted)
1652 Another alternate island venting arrangement
1653 Vent too tall
1654 Plumbing vent clearances
1655 Automatic air vent or air admittance valve |
