Before heading off on vacation, most people think about locking the doors, packing their bags, unplugging unnecessary appliances, and asking someone to collect the mail. But there is one small household detail that often gets overlooked: the kitchen and bathroom sinks.
Imagine returning home after two weeks away, opening the front door, and being greeted by an unpleasant smell. The house looks exactly as you left it, but something in the kitchen or bathroom seems wrong. A drain may be releasing a foul odor, or tiny insects may have appeared around the sink.
Fortunately, a few simple precautions can help reduce the chances of these problems occurring while you’re away.
One popular household tip involves placing a piece of paper over the sink drain and setting an upside-down glass on top of it. Although the trick is often shared as a way to keep insects and unpleasant smells away, understanding what it can and cannot do is important.
Why Can Your Sink Smell After a Vacation?
Most household sinks are connected to plumbing systems designed to prevent sewer gases from entering the home.
A key component is the drain trap, often shaped like a U or P. This curved section holds a small amount of water that creates a barrier between the room and the drainage system.
When you use your sink regularly, fresh water replenishes this barrier. However, if a drain remains unused for an extended period, some of the water can gradually evaporate.
When the trap dries out completely, sewer odors may enter the room.
This is more likely to be an issue in warm, dry conditions or in drains that are rarely used. The amount of evaporation depends on the plumbing setup, temperature, humidity, and length of time the drain remains unused.
The good news is that preventing a dry drain trap is usually straightforward.
What Is the Upside-Down Glass Trick?
The idea is simple: place a small piece of paper over the drain opening and position an upside-down glass over it.
People share this method as a way to discourage insects from emerging through the drain and to cover the opening while the sink is unused.
However, there is an important distinction: an upside-down glass and a piece of paper are not a reliable substitute for the water barrier inside the drain trap.
The glass may cover the drain opening, but it will not prevent water inside the trap from evaporating. Nor should it be considered an airtight seal against sewer gases.
If you choose to use the trick, make sure the glass is stable and cannot easily fall into the sink. Avoid placing it where it could damage a delicate basin or create a hazard.
Think of it as a simple covering method rather than a guaranteed plumbing solution.
The More Important Step: Keep the Drain Trap Filled
If your goal is to prevent sewer odors, the most useful step is to make sure the drain trap contains water before you leave.
Here’s what to do:
- Run water into each sink for several seconds before leaving.
- If you have floor drains or rarely used bathroom fixtures, check those as well.
- Make sure the drains are functioning normally and that there are no signs of leaks or persistent odors.
- If you will be away for several weeks, consider asking someone to check the house periodically.
For drains that regularly dry out, a plumber can recommend a suitable solution. Some situations may call for a trap primer or another method of maintaining the water seal.
Avoid pouring random chemicals or household mixtures down the drain as a preventive measure. These can damage plumbing, create hazardous reactions, or provide little benefit.
Can Insects Really Come Through the Drain?
Sometimes, insects are associated with sink drains, particularly drain flies, which breed in the organic film that can accumulate inside drainpipes.
These tiny flies are often seen resting around bathroom or kitchen sinks. Their presence usually points to a buildup of organic material in a drain or another nearby moist area.
Other pests, including cockroaches, may be attracted to moisture and can sometimes enter buildings through plumbing-related openings or gaps around pipes.
However, not every insect seen near a sink has come through the drain. Flies and other pests may enter through windows, doors, ventilation openings, or small gaps elsewhere in the building.
To reduce the risk, clean the drain opening and surrounding sink before leaving. Remove food scraps, wipe up standing water, and make sure nearby windows and doors are securely closed.
If you regularly see drain flies, cleaning the inside surfaces of the drain and removing the organic buildup is generally more useful than simply covering the opening.
Don’t Forget the Kitchen Sink
The kitchen can be especially vulnerable to unpleasant odors because tiny food particles and grease can accumulate inside the drain.
Before leaving for vacation, remove leftover food from the sink strainer, clean the basin, and wipe down the surrounding countertop.
Avoid leaving dirty dishes, damp sponges, or food scraps in the sink. These can attract pests and create unpleasant smells even if the plumbing itself is working properly.
You should also empty the kitchen bin and make sure no perishable food has been left out.
These small tasks take only a few minutes but can make returning home much more pleasant.
What About Bathroom Sinks?
Bathroom drains can also develop odors and buildup, particularly when soap residue, hair, and other debris accumulate.
Before leaving, remove visible debris from the drain, clean the basin, and run water briefly to replenish the trap.
If you have a guest bathroom that is rarely used, pay particular attention to its sink, shower, and other plumbing fixtures.
A sink that smells strongly of sewage even when its trap contains water may have another plumbing problem, such as a faulty trap or an issue with the venting system. In that case, covering the drain will not solve the underlying cause.
A Simple Vacation Checklist
Before you close the door and head to the airport, take a few minutes to walk through your home.
- Run water briefly in rarely used sinks and drains.
- Clean food scraps and residue from the kitchen sink.
- Wipe down bathroom basins and remove visible debris.
- Empty rubbish bins and avoid leaving food exposed.
- Check for existing leaks or persistent plumbing odors.
- Ask someone you trust to check the property if you will be away for an extended period.
You can still place an upside-down glass over a piece of paper as an extra covering if you find it useful, but don’t rely on this trick alone to prevent odors or pests.
The Bottom Line
The upside-down glass and paper trick is a simple household idea, but its effectiveness is limited. It may cover a drain opening, yet it cannot replace the water seal that normally blocks sewer gases.
The most reliable approach is to prepare your sinks properly, keep drain traps filled, clean away food residue, and address any existing plumbing problems before leaving.
A few minutes of preparation can help you avoid unpleasant surprises when you return from vacation.
And perhaps the most useful lesson is this: sometimes, the best household tricks aren’t the unusual ones circulating online. They’re the simple maintenance habits that prevent problems before they begin.
