Have you ever heard the advice to cover your kitchen sink drain with a piece of paper and place an upside-down glass over it before leaving for vacation? At first, this unusual household trick might seem pointless. However, there are several reasons why people recommend taking precautions around sinks before leaving home for an extended period.
From preventing unpleasant odors to reducing the risk of pest problems, understanding how your plumbing works can help you prepare your home before a trip.
But is the paper-and-glass trick actually necessary? Let’s look at what it might accomplish, what it cannot do, and the more reliable steps you can take before leaving.
Step 1: Understand Why Sink Drains Can Develop Bad Odors
One of the most common reasons a sink develops an unpleasant smell is the buildup of organic material inside the drain.
Food particles, grease, soap residue, and other debris can accumulate on the inside of drainpipes. Over time, this material can produce unpleasant odors.
Fortunately, most household sinks have a plumbing component called a P-trap or another type of trap. This curved section of pipe retains water, creating a barrier that helps prevent sewer gases from entering your home.
When the trap functions properly and contains sufficient water, it generally prevents odors from traveling back through the drain.
However, if a sink remains unused for a long time, some of the water in the trap can evaporate. This is more likely in hot, dry conditions or when a drain is rarely used.
If the water seal disappears, sewer odors may enter the room.
Step 2: Learn What the Paper and Glass Are Supposed to Do
The paper-and-glass method is sometimes presented as a way to protect a sink while nobody is home.
The idea may be to cover the drain opening, keep the area around it protected, or discourage insects from emerging through the drain.
However, this arrangement is not a reliable plumbing solution.
A sheet of paper does not create an airtight seal, and an upside-down drinking glass is not designed to seal a drain. Depending on the shape of the sink and the position of the glass, air and insects may still pass through gaps.
The method also does not prevent the water inside the P-trap from evaporating.
Consequently, although the setup may physically cover the drain opening, it should not be relied upon to prevent sewer gases, stop a plumbing problem, or provide effective pest control.
Step 3: Understand the Role of the P-Trap
The P-trap is one of the most important parts of a household drainage system.
It is designed to retain a small amount of water in a curved section of pipe beneath the sink.
This water forms a barrier between the room and the drainage system.
When the trap is functioning properly, the water seal helps prevent sewer gases from entering the kitchen or bathroom.
Before leaving for an extended vacation, running water into a sink that has not been used recently can help replenish its trap.
For ordinary household plumbing, maintaining this water seal is much more useful than placing paper and a glass over the drain.
If you notice persistent sewer odors despite running water, there may be a dry trap, a leak, a venting issue, or another plumbing problem that needs investigation.
Step 4: Reduce the Risk of Insects Entering Your Home
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