Most people run through the usual tasks before heading out on vacation—locking up, adjusting the thermostat, discarding old food, and watering the plants. But there’s one tiny detail that often gets missed, and it can lead to an unpleasant surprise when you return home. When a house sits unused for several days or weeks, a little-known part of the plumbing can allow mild odors to creep in, making your homecoming less relaxing than you’d hoped.

Under every sink sits a curved pipe called a P-trap. Its job is to hold a small pool of water that blocks sewer gases and insects from traveling up through the drain. During normal daily use, this barrier stays intact. But when a sink goes unused for long periods, the water inside the P-trap can slowly evaporate. Once that happens, faint smells can drift upward, settling into your bathroom or kitchen before anyone even opens the front door.

There’s an easy fix that takes less than a minute. Before you leave, place a paper towel over the drain and set an upside-down glass on top of it. This creates a simple, lightweight cover that helps keep odors down and makes it harder for insects to enter the pipe. It’s often more reliable than rubber stoppers, which can loosen on their own while you’re away. Best of all, you likely already have everything you need in your kitchen drawer.

For an extra touch of freshness, give the sink a quick clean before covering it. Rinse with warm water, add a splash of vinegar to clear away residue, and wipe the basin dry. Then place the paper towel and glass over the drain. This small step helps ensure you return to a home that feels welcoming—not musty. Sometimes the simplest habits offer the biggest peace of mind.