Why are roaches coming up through my drains?
Large roaches crawl up through dry P-traps in bathtubs and sinks that haven't been used regularly, leaving them trapped because they cannot climb out of smooth porcelain surfaces. This creates a recurring infestation in master bathrooms and kitchens during specific times of the year, forcing homeowners to constantly deal with bugs emerging directly from their plumbing lines.
What the numbers show
Counted from the threads quoted below. How we count
- The most recent one is from September 2026.
- This comes up 24.4× more often in r/Pestcontrol than across the site as a whole.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Running water periodically to refill dry P-trapsDid this help you?
- 2Putting baby or mineral oil in the drain to prevent trap evaporationDid this help you?
- 3Duct-taping the overflow cover shutDid this help you?
- 4Dusting plumbing access areas with insecticides like Nibor-DDid this help you?
- 5Using roach gel bait or aerosol spraysDid this help you?
- 6Hiring a plumber to run a camera or perform a smoke test for broken pipesDid this help you?
- 7Killing the spider upon discoveryDid this help you?
- 8pull the dishwasher out of the cabinet and then seal the holes that exist at the back of the cabinetDid this help you?
- 9Call an exterminator and/or talk to your landlordDid this help you?
- 10shoot a full can of expanding foam insulation in thereDid this help you?
- 11using DrainoDid this help you?
- 12using Green GobblerDid this help you?
- 13pouring baking soda and vinegar down the drainDid this help you?
- 14pouring boiling water and bleach down the drainDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Recently I ended up with five roaches in my tub. They can't climb out.”source ↗
“This time of year I occasionally I see roaches around my house, specifically around the master bath and kitchen.”source ↗
“The tub hasn't been used in a decade and I have to clean out dust occasionally when i get rid of the bodies...”source ↗
“I did battle with one of these fuckers about a month ago in my shower. Biggest one I've ever seen”source ↗
“So I’m living in the basement of an apartment complex and it’s only been 2 and a half months and i’ve seen 5 centipedes in this place. Almost all of them are in my shower.”source ↗
“I’ve used Draino, that Green Gobbler thing, baking soda and vinegar, boiling water and bleach EVERYTHING and I come home after a long day to find another one stuck in the tub with no way out.”source ↗
“You got a spider guarding the drain, that's the nastiness”source ↗
“Ohhh I seen, and killed it.”source ↗
“Are these dishwasher gaps normal? We just moved into a townhome and roaches are coming in and out of these gaps. How would I seal them?”source ↗
Where this came up
People with this problem also raised
- 12Tree roots growing inside drain pipes
- 48Water keeps getting in the house during heavy rain
- 3How to tie in a vent line and shower drain in tight spaces
- 46Why does my new plumbing still have bad water pressure and risky joints?
- 5Why does the drain snake keep coming out the other drain?
- 14Where do I run the vent for a washer installation?