Big Roaches in the Tub? Your P-Trap is Dry.
Found a huge roach in the bathtub after vacation? Your P-trap dried out. Learn how sewer roaches enter through dry drains and how to stop them.
You come home from a two-week vacation. You walk into the bathroom, and there is a massive reddish-brown cockroach in the bathtub.
"My house is clean!" you scream. "Where did it come from?!"
It came from the sewer.
The Dry Trap Theory
Under every sink and tub, there is a U-shaped pipe called a P-trap. It's designed to hold water. That water acts as a seal that blocks sewer gas... and bugs.
When you go on vacation (or don't use the guest bathroom for a month), that water evaporates. The seal breaks.
American Roaches (which live in the city sewer lines by the millions) smell the fresh air and crawl right up the pipe and into your tub.
The Instant Fix
Run the water.
Seriously. Go to every sink, tub, and floor drain in your house and run the water for 30 seconds. This refills the trap and re-establishes the barrier.
If you have a drain you rarely use (like in a basement floor), pour a cup of mineral oil down it. Oil doesn't evaporate like water, so the seal lasts for months.