Preparing your home before a trip often includes locking doors, unplugging appliances, and adjusting the thermostat. Recently, a viral household tip has suggested placing a sheet of paper over a sink drain and covering it with an upside-down glass to help prevent sewer odors and insects from entering the home while you’re away. Although the idea is based on a real plumbing concept, experts explain that the method may not provide the reliable protection many people expect. Understanding how household drains actually work can help you choose more effective solutions before leaving for an extended period.
The most important component is the P-trap, the curved pipe located beneath sinks, bathtubs, and showers. This pipe is designed to hold a small amount of water at all times, creating a natural barrier that blocks sewer gases and helps prevent insects from traveling through the plumbing system. If a drain remains unused for several weeks, especially during hot or dry weather, the water inside the P-trap can gradually evaporate. Once that protective water seal disappears, unpleasant odors and, in some cases, small pests may be able to enter through the drain.
Although placing paper and an upside-down glass over the drain may appear to add an extra layer of protection, it is unlikely to create a complete airtight seal. Moisture can also soften the paper, reducing its effectiveness over time. Instead of relying on temporary household items, plumbing professionals generally recommend refreshing the water in every sink, shower, floor drain, and bathtub before leaving. After running water through each fixture, use the existing drain stopper, a rubber drain plug, a silicone drain cover, or tightly secured plastic wrap if additional coverage is desired.
For longer vacations, homeowners can take one extra preventive step by adding a small amount of mineral oil to drains after running the water. The thin layer of oil helps slow evaporation, allowing the water seal inside the P-trap to last longer. Combined with properly sealed drains and routine plumbing maintenance, these simple preparations can help reduce unwanted odors and keep your home fresh while you’re away. A few minutes of preventive care before traveling can provide greater peace of mind and make returning home much more pleasant.