In conclusion, while the premise behind this hack is based on a real plumbing principle, the method depicted in the photo is not a reliable means of sealing your drains.
Prepping Your Drains Before Leaving Town: The Right Way
If you want to avoid bad odors, dried-up traps, and unwanted insects when returning from your trip, follow these steps to prepare your drains:
Step 1: Fill Up Your Traps
Before you leave for a trip, run water through each sink, shower and tub for approximately 10-20 seconds. Remember to include laundry drains or floor drains if you have them, and also flush all toilets once.
Refilling your traps with water will ensure that your water seal remains intact in all of your P-traps.
Step 2: Properly Seal Your Drains
If you’re planning to be away for an extended period of time, you’ll want to seal the drain openings. Here are a few options:
Use the existing stoppers (simply close them) and use a sink plug or rubber stopper that fits tightly;
Use silicone drain covers (these are super convenient and reusable);
Or even a piece of plastic wrap or painters tape in a pinch
Your goal is to minimize evaporation and create a physical barrier in the unlikely event that the water evaporates from your P-traps.
Step 3 (Optional for Longer Trips): Add Some Mineral Oil
This is another plumbing trick that I was taught by a 30+ year veteran plumber. Once you’ve run water through your drain, simply pour in about a tablespoon of mineral oil. This will float on top of the water and slow down evaporation dramatically.
