Before going on vacation, most people carefully lock the doors, unplug unnecessary electronics, empty the refrigerator, and make sure their valuables are secure. But there’s one small part of the home that is surprisingly easy to overlook: the sink and its drains.

Kitchen and bathroom drains contain traps designed to hold a small amount of water. This water creates a barrier that helps keep sewer gases and unpleasant odors from entering your home. When a house remains unused for an extended period—particularly during hot weather—the water inside these traps can slowly evaporate.

If enough water disappears, you might return from vacation and notice an unpleasant smell coming from a sink, shower, bathtub, or floor drain. Rarely used drains can be especially vulnerable because their traps may already contain less water before you leave.

Before heading away, run water briefly through sinks, showers, tubs, and other drains that aren’t used regularly. This helps ensure the traps are properly filled. Also check for slow drains or leaks rather than ignoring them until after the trip.

For longer absences, homeowners sometimes take additional measures to slow evaporation from rarely used drains, but it’s important to use methods appropriate for the plumbing system.

It takes only a few minutes before leaving, yet checking your drains could make coming home much more pleasant. After all, nobody wants their relaxing vacation to end with a mysterious odor waiting at the front door.