Covering Your Sink Before Vacation? Surprisingly, Here’s What REALLY Works

Before heading out on vacation, most people have a mental checklist, and apparently it includes covering the sink drain.

We usually lock the doors, unplug a few appliances, take out the trash, and double check that you packed your passport.

Lately, though, another item has started appearing on social media.

According to countless viral videos, placing an upside down glass, a plastic bag, or even a shower cap over your sink drain can stop sewer smells and keep insects from entering your home while you’re away.

It sounds clever, and millions of people have shared the tip. The problem is that plumbers say it doesn’t really do what people think it does.

Why your sink drains usually don’t smell

Every sink, shower, and bathtub has something called a P-trap hidden underneath. If you’ve ever looked under a bathroom sink, you’ve probably noticed the curved section of pipe that forms a U shape.

That bend isn’t there by accident.

Its job is to hold a small amount of water after every use. That water creates a barrier between your home and the sewer system. As long as the trap contains water, unpleasant sewer gases cannot travel back into the room. The same water barrier also helps block drain flies and other tiny insects.

Because of that simple design, most homes already have protection built in.

Does the upside down glass trick work?

Not really.

A drinking glass resting over the drain doesn’t create an airtight seal. Even if you tape plastic over the opening, air can still escape around tiny gaps, making the trick far less effective than people assume.

More importantly, you’re trying to solve the wrong problem.

Sewer odors usually appear only when the water inside the P-trap has completely evaporated. Under normal conditions, that doesn’t happen during a weekend getaway or even a two or three week vacation.

Unless a drain hasn’t been used for several months, there’s a good chance the trap will still contain enough water to do its job.

Instead of covering every drain in the house, run water through each sink, shower, and bathtub before leaving.

Thirty seconds is usually enough.

Doing this refills every P-trap with fresh water, restoring the seal that keeps odors and pests where they belong.

It takes less than two minutes to walk through the house, yet it’s one of the easiest ways to avoid unpleasant surprises when you return.

If you’re going away for several days, there are a few precautions that make far more sense than balancing glasses over your drains.

Turn off the main water supply if possible. A burst pipe or leaking washing machine hose can cause serious damage while nobody is home.

Unplug small kitchen appliances such as coffee makers and toasters. Besides reducing standby power use, it also protects them from electrical surges.

Finally, adjust your thermostat instead of switching it off completely. Keeping your home at a moderate temperature helps prevent frozen pipes during winter and excess humidity during hot summer months.

The upside down glass trick is one of those internet hacks that sounds convincing because it’s simple.

In reality, your plumbing already has a built in defense against sewer gases. A quick run of fresh water through each drain does far more than covering sinks with household items.

Before your next trip, spend those extra couple of minutes on the basics instead. You’ll return to a home that smells just as fresh as when you left.