The Surprising Reason Some People Cover Their Sink Before Leaving Home

The paper-and-glass trick taps into a real issue: when the water in your P-traps evaporates, the barrier between your home and the sewer system breaks, letting odors and insects sneak in. But that viral setup is flimsy at best. An upside-down glass almost never forms an airtight seal, paper quickly absorbs moisture, and air—and smells—still move freely. You’re trusting your peace of mind to a balancing act that fails the moment conditions change.

A far better approach is quietly simple. Before you leave, run water in every sink, shower, and tub for 10–20 seconds, flush all toilets, and don’t forget basement floor drains or laundry standpipes. For trips longer than a few weeks, use real seals: built-in stoppers, rubber or silicone drain covers, or tightly taped plastic wrap. If you’ll be gone a long time, add a tablespoon of mineral oil to each filled trap to slow evaporation—and consider shutting off the main water supply. No gimmicks, no viral hacks, just proven plumbing habits that actually protect your home.