With an “S” trap drain, the trap is easily siphoned dry with each use and the water seal no longer exists. A properly installed “P” trap will always maintain a water seal.

If its edge is raised, it will trap water. After you install the CPE liner, cut a hole at the drain opening. Use a plastic plumbing drain with a clamping ring to seal it to the liner.

Heater drippage eroding concrete floor Published: Oct. 28, 2007, 3:41 p.m.