Before leaving home for a vacation, most people have a familiar checklist.

Lock the doors.

Close the windows.

Unplug unnecessary electronics.

Take out the trash.

Check that appliances are switched off.

Make sure valuables are safely stored.

But there is one small area that is easy to overlook: the sink.

Whether it is in the kitchen, bathroom, laundry room, or another part of the house, a sink can become surprisingly important when a property is left empty for several days or weeks.

When plumbing fixtures are not used regularly, changes can occur inside the drain system. Water in the trap can gradually evaporate, particularly during warm or dry conditions. Once that water barrier becomes reduced or disappears, odors from the drainage system can potentially travel back into the home.

There is also another issue.

A quiet, unused home can become attractive to insects looking for moisture or food sources.

Fortunately, homeowners can take several simple steps before leaving.

One commonly shared household trick involves an upturned glass and a piece of paper placed over the sink or drain area. While this is not a substitute for proper plumbing maintenance, it can serve as a simple reminder and physical barrier against some unwanted problems.

Why Does the Sink Matter When You’re Away?

A sink may seem completely harmless when it is not being used.

But the plumbing underneath it is connected to a larger drainage system.

Most household sinks have a curved section of pipe known as a trap. The trap is designed to hold a small amount of water.

That water serves an important purpose.

It helps prevent gases and odors from the drainage system from traveling directly into the living space.

Under normal circumstances, the trap stays filled because the sink is used regularly.

When a home remains empty for an extended period, however, the water can gradually evaporate.

The warmer the conditions, the faster evaporation may occur.

If the water level becomes too low, the barrier becomes less effective.

That can allow unpleasant smells to enter the room.

Why Warm Weather Can Make the Problem Worse

Temperature can influence how quickly water evaporates.

During warmer months, evaporation can happen more quickly, particularly in rooms that become hot while the home is unoccupied.

A bathroom or kitchen with poor ventilation may also develop stale odors when it remains closed for an extended period.

This does not mean every vacation home will develop a plumbing problem.

Many homes remain perfectly fine while their owners are away.

But taking a few preventative steps can make returning home much more pleasant.

Nobody wants to open the front door after a relaxing vacation and immediately notice a strange sewer-like smell.

The Role of an Upturned Glass

The idea behind placing an upturned glass over a sink is straightforward.

The glass can act as a physical cover over the drain area, depending on the design and size of the sink.

It can also make it obvious that the sink has been prepared before leaving.

Some homeowners combine the glass with a piece of paper placed beneath or around it.

The paper can help reveal whether something has moved or whether moisture has reached the area.

However, it is important to understand what this trick can and cannot accomplish.

An upturned glass does not prevent water inside the plumbing trap from evaporating.

It also does not repair defective plumbing, stop insects from entering through every possible route, or eliminate existing drain odors.

Its usefulness is primarily as a simple physical barrier and visual reminder.

For stronger protection, homeowners should address the plumbing itself.

A Better Step: Check the Drain Trap

Before leaving for an extended vacation, it can be helpful to make sure each sink’s drain trap contains water.

Simply running the faucet for a short time before leaving can replenish the trap.

The same principle applies to other plumbing fixtures that may not be used while you are away.

Bathroom sinks, showers, tubs, and floor drains can all potentially experience evaporation.

If a particular drain is rarely used, it may deserve extra attention.

Homeowners should also remember that some plumbing fixtures have different designs, so a general household tip may not apply identically to every drain.

What About Insects?

Insects are another reason some people pay attention to drains before leaving home.

Certain small insects are attracted to moisture and organic material that can accumulate inside drains.

Fruit flies and drain flies, for example, can become a nuisance when conditions are favorable.

Other household pests may also seek water sources, particularly during hot weather.

A clean and dry home is less attractive to many pests, but no simple drain cover can guarantee that insects will stay away.

The best approach is to combine several preventative measures.

Clean visible food residue.

Empty garbage bins.

Avoid leaving dirty dishes in the sink.

Wipe away standing water.

Clean drains periodically.

Seal obvious cracks or openings around plumbing where appropriate.

These simple actions can reduce the number of opportunities pests have to find food and moisture.

Do Not Forget the Kitchen Sink

The kitchen sink deserves particular attention because food residue can accumulate around the drain.

Even tiny amounts of grease, food particles, or organic material can contribute to unpleasant smells or attract insects.

Before leaving for vacation, thoroughly clean the sink basin and surrounding surfaces.

Run the disposal, if you have one, according to the manufacturer’s instructions and clean it appropriately.

Do not assume that pouring large amounts of harsh chemicals down the drain is necessary.

In fact, using cleaning chemicals incorrectly can create plumbing or safety problems.

A basic cleaning routine is often sufficient for ordinary household maintenance.

Bathroom Drains Need Attention Too

The bathroom can present similar issues.

Hair, soap residue, skin oils, and other material can accumulate in drains over time.

A bathroom that remains unused for weeks may develop a stale smell if the plumbing traps dry out.

Before leaving, clean the sink and shower areas.

Make sure drains are free of obvious buildup.

Run water through fixtures shortly before departure.

Then consider covering vulnerable drains where practical.

Other Things to Check Before Vacation

The sink is only one part of preparing a home for an extended absence.

A few additional checks can reduce the likelihood of unpleasant surprises.

Make sure food is properly stored.

Take out perishable garbage.

Check for leaks beneath sinks.

Look at toilets and visible plumbing connections for signs of moisture.

If your home has a water shutoff valve and you know that your plumbing system and appliances are suitable for being isolated, consider whether shutting off the main water supply makes sense for your situation.

Some homeowners also arrange for someone they trust to check the property periodically.

That can be particularly useful during longer trips.

A small leak that goes unnoticed for several weeks can cause considerably more damage than one discovered quickly.

What Should You Do When You Return?

When you arrive home after vacation, remove any temporary covers and check the sinks and drains.

Run water through fixtures that have not been used.

If you notice an unusual smell, allow water to run for a short period and ventilate the room.

Persistent sewer odors, slow drainage, unusual bubbling, or recurring smells may indicate a plumbing issue that requires professional attention.

Do not simply cover up a persistent odor and assume the problem is solved.

A professional plumber can investigate whether the issue involves a dry trap, venting problem, damaged pipe, or another plumbing fault.

The Simple Vacation Checklist

Before leaving your home, consider this quick routine:

• Clean kitchen and bathroom sinks.

• Remove food particles and garbage.

• Run water through infrequently used drains.

• Check underneath sinks for leaks.

• Make sure drain traps have water.

• Consider covering vulnerable drains where appropriate.

• Keep food properly sealed.

• Remove perishables.

• Check for standing water.

• Arrange a property check if you will be away for an extended period.

These steps take only a few minutes but can help make your return home more comfortable.

Final Thoughts

The idea of leaving an upturned glass and piece of paper in the sink may sound unusual, but it reflects a broader principle of home maintenance: small preventative actions can sometimes save you from unpleasant surprises.

The glass itself is not a magical solution.

It cannot prevent every plumbing odor, stop all insects, or replace proper maintenance.

The more important step is understanding why drains can become problematic when a home sits unused. Water in plumbing traps can evaporate, food and residue can create odors, and stagnant conditions can provide opportunities for pests.

So before heading to the airport or starting your road trip, take a few extra minutes to inspect your sinks and drains.

A clean sink, a properly filled trap, and sensible precautions can help ensure that the first thing you notice when you return is not an unpleasant smell—but the relief of finally being home.