Entomology (Study of Bugs)/Fleas in the bathtub



Good morning Ed,

About 4 weeks ago, fleas started appearing in our guest bathtub. We don't use this tub at all other than to wash our dog, which we had done about 4 weeks prior to the fleas showing up. I'm assuming there were flea eggs on the dog that got washed in the drain and have now started hatching, but we're unsure where they are coming from.

The dog and cat are free of fleas and we've seen no evidence of them anywhere in the rest of the house. The bathtub is deep enough that the little buggers can't jump out. I've attached two photos of one to confirm it is a flea and not a springtail.

We've tried drain cleaner, borax, drowning...nothing seems to work to get rid of them. We can keep the drain plugged and they don't get out, but once it's unplugged, they're back. Can you tell me how we can kill them once and for all?

Thank you!

Dear Karen - I'm not going to say that it is impossible for the fleas to be coming from the drain simply because there are very few things in biology that truly are impossible, but I do think that possibility is exceedingly unlikely. Although flea larvae need high humidity in order to develop, they also avoid areas that flood or otherwise are wet. They usually are found in or very near where pets spend their time, either in carpeting, upholstered furniture, cracks in floorboards, etc., feeding on bits of organic debris. They somehow must be jumping into the bathtub, then becoming trapped there. When you say that your pets are free of fleas, does that mean that they have been treated for fleas (such as with Frontline)? If so, I can only suggest that you wash all pet bedding and thoroughly vacuum all floors and upholstered furniture on a regular basis, carefully sealing and disposing of the vacuum cleaner bags after each procedure. Then, if the problem still persists, you may have to have a professional pest control operator apply treatment such as an IGR (insect growth regulator). See http://tinyurl.com/aejfwul and http://tinyurl.com/bfor5z9 for additional information on this subject.

Hope this helps,

Entomology (Study of Bugs)

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Ed Saugstad


Will accept most questions in general entomology, including those related to medical entomology, taxonomy, ecology, arthropod surveillance, and pest management. If you are requesting a 'mystery bug' identification, PLEASE either attach an image to your question, or post an image on a web page (such as Flickr) so that I can look at it, as verbal descriptions frequently are insufficient for a definitive identification.


21 years in the U.S. Army as a medical entomologist; duties varied from surveillance of pest populations (including mosquitoes, cockroaches, ticks, and stored products pests) to conducting research on mosquito-virus ecological relationships and mosquito faunal studies. Ten years as a civilian analyst for the Department of Defense, primarily on distribution of vector-borne diseases worldwide. Limited experience on surveillance of agricultural insects in North Dakota and Indiana.

Entomological Society of America, West Virginia Entomological Society, Society for Vector Ecology, National Speleological Society, West Virginia Association for Cave Studies.

American Journal of Public Health, Contributions of the American Entomological Institute, Japanese Journal of Sanitary Zoology, Journal of Economic Entomology, Mosquito News, and Mosquito Systematics.

B.S. in entomology from North Dakota State University in 1963, M.S. in entomology from Purdue University in 1967.

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