[Escape Artist]

Originally Posted by TCNY61

There is a curve in the drain called a trap that holds water to block any sewer gasses and smell. If that water evaporates the sewer gasses will not be blocked and will enter the house.

We used to shut off the valve to our toilet which prevents leaks and/or possible flooding in the home. But I think some water remains down in the drain.

[rustyp]

Originally Posted by Escape Artist

Why do you cover the toilet bowl with plastic wrap?

Long story short - Do not cover the toilet with plastic wrap unless you turn off the water supply for the house or that toilet. The water in the tank will still evaporate and when low enough call for water to be added. Usually when one flushes a toilet the tank goes almost empty and fills up rapidly creating a slamming effect on the tank shutoff valve. The case I describe of losing a slight amount of water and fills back up total momentum has not been reached and there is a chance the water will not shut off. Normally not a problem since the tank has an overflow. The overflow pushes water out the toilet trap.However with the plastic wrap over the toilet it is possible to vapor lock and the water won't push out the trap. Water still runs and overflows out the top of the tank flooding your house.

How do I know this ? $28000 worth of experience.

Another tip. The water in your sink traps will evaporate over a long period of time and the sewer gas and bugs can get in. Solution - fill zip lock bags with water and set over the drains. The bag will conform to the shape of the drain and create an air tight seal.