Do fleas drown in water?

cat flea drowning

The Flea Swimming Olympics

Img 1 Cat fleas don’t drown quickly because they don’t break the surface tension of water.


Fleas can survive for up to 7 days when dropped in water. When submerged, it takes fleas at least 24 hours to drown. Adding a couple drops of dish soap to the water will speed up the process. Dish soaps contain surfactants, which reduce water’s surface tension and cause fleas to sink and drown.


Insect respiratory systems are resistant to oxygen deprivation. Insects won’t drown when submerged in water for only a few hours. As far back as 200 A.D., Claudius Aelianus reported that flies couldn’t be easily drowned.

Drowning Fleas in Water

How Long it Takes Fleas to Drown

Fleas can survive up to 24 hours while submerged in water. They can be revived if they’re removed up this point. When fleas are placed in water, not submerged, they’re nearly impossible to drown. In one study, seven squirrel fleas were dropped in water. Only one died within 24 hours. The others lived up to seven days.

Why Fleas don’t Drown Easily

Fleas, and other insects, have wax-covered cuticles. The outer waxy layer repels water and makes them non-wettable. The oil-like coating also helps fleas slide through host hair. It’s likely that the cuticle wax extends into the trachea and prevents water from entering the respiratory system.

Fleas don’t break the surface tension of water due to their water-repellent cuticle and small size Img 1. In natural settings, they’ll remain on the water’s surface, flailing around and possibly crawling out. Rubbing petroleum jelly on the water container’s rim can help prevent escape.

Surfactants & Soapy Water

Using soapy water as an insecticide dates back hundreds of years. Today, fleas are commonly drowned by adding dish soap to water. Examples: (1) Making a flea trap by placing a plate of soapy water beneath a lamp. (2) Drowning fleas in a bowl of soap-water as they’re combed off of a cat.


Making Fleas Sink

Dishwashing liquids, such as Dawn, contain surfactants which lower the surface tension of water. It only takes a couple drops of detergent to reduce the water’s surface tension enough for fleas to sink and drown.

Dawn dish detergent is most commonly used for flea control. However, Jet-Dry is a more concentrated surfactant and doesn’t foam. It may a better option if fleas are jumping out of the water by climbing onto soap bubbles and suds.

Counteracting Cuticle Wax

The surfactant properties of dish soap also make insects more wettable. The once hydrophobic waxy cuticle will no longer repel water. As a result, water can enter into their spiracles and respiratory systems, displacing air and drowning the insects. Additionally, sudsy water may physically block the spiracles, preventing the exchange of air and causing suffocation.


It’s theorized that soaps work as insecticides by breaking down cell membranes and by removing cuticle wax. As a result, insects can’t retain water and they rapidly desiccate. Soaps may also act as growth regulators, interfering with the cellular metabolism of insects.

Experiments done with glycerine soaps have shown little to no effect on fleas. It takes up to four days for fleas to die in 50% glycerine and 50% water.

Bathing Pets with Dish Soap

Dish liquids are sometimes used as alternatives to flea shampoos for pets. However, dish soap isn’t made for animals. It’s much harsher than pet shampoos and will remove the protective oils from an animal’s haircoat. As a result, their skin can get extremely dry and irritated. Even with the more gentle, pH balanced shampoos, it’s recommended not to bathe pets more than once a month. Avoid using dish soap on pets with skin infections.

Drowning Fleas in Vegetable Oil

Homemade flea traps sometimes use vegetable oil to drown fleas. Vegetable oil has around half the surface tension of water. It’s also more viscous. Fleas jumping into oil will quickly get trapped and sink, eventually drowning or suffocating.

Washing Machines & Dryers

Most flea control programs recommend frequently washing animal bedding and rugs. When laundering these items, run the washing machine at 140°F for ten minutes. Then use the highest heat setting on the dryer.


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  • Anonymous January 22, 2016, 12:15 am

    thank you

  • KayecJachimski May 17, 2017, 5:23 pm

    My 16 year old cat suffered a stroke from being anemic and I was warned by his family vet, an emergency er Servicev in March of 2015 when I took him in after a cyst on his shoulder exploded and I could not stop the bleeding. If only I had I could have saved a few dollars. I knew the surgery on a 15 yr.old cat would be expensive. They found 3 fleas on him and I said that’s impossible. I raised 4 cats prior to him and they all passed the flea comb test. Truth be told I wouldn’t know what one looked liked like . I was treated as if I did it Intentionally as is was brought up 4 times. W/O my knowledge he was dipped for fleas. NJ had the worse breakout of fleas in the summer of of 2016 and unbeknownst to all their was a flea break out on the grounds of our condo property between Oct – Jan 2016:. All 4 of us in my building had fleas and we did not not see each other to tell one another. I feel guilty because my cat had a stroke Saturday afternoon and I I was unable to get him to a Veterinary hospital until 8 AM Sunday morning. I was shocked to hear then the news he had stomach cancer unrelated to the stroke that left him unable to walk on his own. I did my my best keeping him comfortable – we had the best night the prior evening when I had brushed my 26 pound cat , played with his birdie and he was hugging me that night. I just wish I would have known it was our last night. My cat should have been named finicky because I had problems trying to to feed him after his food was cancelled in 2015. .How do I forgive myself for him turning anemic? I have an illness CRPS / that became so bad I was unemployed in 2002 – two months after I adopted Cee Jay so he knew life along with his older brother and sister to be waited on hand and foot. The feeling was mutual – on my bad days they sat with me for most of the day . I have not had any cats in my home since January . With this being May 17 – 20 weeks with out cats what product on your list would you recommend to finish off the last few Fleas in my condo ? Thank you for your recommendations- Kate

    • Adam Retzer May 23, 2017, 2:36 pm

      Kate, I am sorry to hear about your situation. It sounds like you went through a lot lately.

      Regarding the March 2015 incident, fleas can be difficult to detect, especially when the on-host population was only 3. Hopefully the impression you got from the doctors was just an impression.

      You shouldn’t need to use any product to finish off the last fleas. The best thing you can do to speed up their removal is to vacuum more regularly. But, without a host, cat fleas can’t survive or reproduce (humans aren’t sufficient hosts).

  • Noelia Davila May 28, 2017, 12:45 am

    How long do I have to leave Dawn dish soap on my hair to desiccate fleas?. I’ve bought something for $30.00 a couple of weeks ago, but I’m seeing tiny dog fleas. No more dogs, treatment, will continue to vacuum, will get another treatment if I have to.

    • Adam Retzer May 29, 2017, 12:51 pm

      I don’t know a specific duration, but it shouldn’t take long. A normal shampooing should do it. The Dawn will remove the insect’s protective oily coating so they can’t repel or retain water.

      Keep in mind, the Dawn will also remove the natural oils on your scalp. This can lead to itching and dryness. Plus, it’s not common for fleas to live on people or in their hair.

  • Bonnie October 16, 2017, 5:46 pm

    I used both NexGuard and Frontline Gold within the last month and my morkie still has fleas. I have bombed my house and sprayed and given several baths and can’t kill them. Any suggestions?

    • Adam Retzer October 17, 2017, 11:25 am

      Please see our page on How to get rid of fleas for comprehensive control info. It’s important to keep in mind that it will take around 8 weeks before an infestation ends. So seeing fleas after a month of treatment is normal, though the numbers should be diminishing.

  • Chris walton September 2, 2018, 6:51 am

    Can ticks drown

    • Adam Retzer September 2, 2018, 10:46 am

      I do not specialize in ticks. They should drown, but I don’t know the specifics.