P-traps drying out

[RET FF]

I seem to recall reading somewhere a tip about pouring a small amount of vegetable oil in the p-traps to keep the water from evaporating. Can anybody confirm or debunk that myth?

[rgvtexan]

It works but is a little messy, I just use RV Antifreeze in drains and toilets. It evaporates slower than water. Use the stopper or cover with plastic wrap. A zip lock baggie part full of water, works well for shower drains. This is what I use in the S&Bs.

[dennis45]

Here is another alternative that cures the problem.

Sewer Smell Inside Your RV? HepvO Waterless P-trap to the Rescue

[NHRA225]

Vegetable Oil or Olive Oil is what I've been using for years now to keep the Gray tank odor from coming in.