Bed bugs are extremely vulnerable to water. Their flat bodies and the location of their breathing holes make even brief contact with water potentially fatal, and research from UC Riverside confirms that bed bugs actively avoid wet surfaces. That said, the details matter: plain water, soapy water, and hot water all work differently against these pests.
Why Water Is So Dangerous to Bed Bugs
Bed bugs breathe through tiny openings called spiracles that sit along the underside of their bellies. Their bodies are unusually flat, which means when a bed bug contacts a water surface, it gets stuck. The water seals over those breathing holes like a film, and the bug suffocates. Unlike rounder insects that might float or scramble free, a bed bug’s flat profile works against it.
This isn’t just a minor inconvenience for them. Researchers at UC Riverside found that water’s surface tension is so adhesive against bed bugs that it functions almost like a trap. Professor Dong-Hwan Choe, the entomologist who led the research, described water as genuinely dangerous from a bed bug’s perspective. Every life stage, from young nymphs to adult males and females, showed the same avoidance behavior. They wouldn’t even walk on damp paper.
Plain Water vs. Soapy Water
Plain water can kill bed bugs, but soapy water does it faster and more reliably. Soap breaks down the waxy outer coating on a bed bug’s body, which normally provides some water resistance. It also reduces the surface tension of the water itself, meaning the bug sinks instead of getting trapped on the surface.
Cornell’s integrated pest management program recommends keeping a bucket of soapy water nearby when inspecting for bed bugs. If you find a live one, dropping it into sudsy water will partly disable it almost immediately and drown it shortly after. This is a practical, low-tech way to deal with individual bugs you encounter during an inspection or cleanup.
Hot Water and Laundry
Temperature is the real weapon when it comes to using water against bed bugs in clothing and bedding. Washing clothes in hot water and drying them at temperatures above 122°F for 20 minutes kills all life stages, including eggs. That threshold is important because eggs are the hardiest stage and can survive conditions that kill adults.
For items like suitcases that can’t go in a machine, hand-washing with the hottest water you can safely use (100°F to 120°F) combined with a scrub brush along seams and folds is effective. The University of Minnesota Extension recommends focusing the brush on creases where bugs and eggs tend to hide, since the mechanical scrubbing dislodges them while the hot soapy water finishes the job.
The dryer is actually more important than the washer in most cases. Even if your washing machine doesn’t reach lethal temperatures, a standard home dryer on high heat easily exceeds 122°F. Running infested fabrics through a full hot dryer cycle is one of the most reliable DIY methods for killing bed bugs.
Can Bed Bugs Spread in Swimming Pools?
Bed bugs spreading through swimming pools or hot tubs is essentially a non-issue. These insects avoid moisture so intensely that they won’t willingly go near standing water, let alone survive submersion in a chlorinated pool. Bed bugs are hitchhikers that travel on luggage, clothing, and furniture. They have no reason to be near a pool, and if they ended up in one, the combination of water contact over their spiracles and chemical treatment in the water would kill them quickly.
Water as a Practical Control Tool
Understanding bed bugs’ vulnerability to water opens up a few useful strategies. One classic approach is placing the legs of your bed frame in shallow dishes of water (or soapy water). Bed bugs crawling up from the floor to reach you at night would have to cross that water barrier, and as the research shows, they won’t willingly do it. Adding a drop of dish soap to the water makes it even more effective by eliminating any chance a bug could survive contact with the surface.
Water alone won’t solve an infestation. Bed bugs that are already in your mattress, headboard, or bed frame won’t encounter those water traps. But as one layer of a broader approach, water barriers and hot laundering are genuinely useful tools. The fact that bed bugs fear water this much is a vulnerability worth exploiting.