We're going on vacation, and my in-laws told me to cover my sink drain with a piece of paper and place a glass upside down over it.
2. Preventing Dried-Out P-Traps and Sewer Gas
Every drain in your home features a U-shaped pipe underneath it called a P-trap. Under normal circumstances, a small amount of water always sits at the bottom of this "U." This water acts as a natural, airtight seal that prevents foul-smelling, dangerous sewer gases from traveling up the sewer line and entering your home.
The Evaporation Risk: If you are going away for an extended vacation—especially during hot summer months or in a dry climate—the water sitting in that P-trap can slowly evaporate.
The Smell: Once the water barrier dries out, there is nothing stopping toxic sewer gases (like methane and hydrogen sulfide) from venting straight into your kitchen or bathroom.
Flipping a glass over the drain acts like a cap. It drastically slows down the evaporation process by trapping the humidity inside the pipe, ensuring your P-trap stays full and your home smells fresh when you walk back through the door.
How to Do It Effectively
If you want to put your in-laws' advice to use before your next trip, here is the best way to execute the trick:
Run the Water: Right before you leave, run the faucet for a few seconds to ensure the P-trap is entirely full of fresh water.
Add the Seal: Place a small piece of thick paper (like a index card, a piece of parchment paper, or a scrap of cardboard) directly over the drain opening.
The Weighted Glass: Place a heavy drinking glass or a ceramic mug upside down over the paper. The weight of the glass ensures the paper stays flush against the sink surface, keeping the seal tight.
Bonus Tip: Don't forget the other drains! This trick is incredibly useful for guest bathroom sinks, showers, and floor drains that don't get used very often, as those P-traps are always the first to dry out.
It turns out your in-laws weren't teasing you or passing along a myth—they were giving you a brilliant, zero-cost piece of preventative home maintenance. Now you can enjoy your vacation with total peace of mind
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