The short answer is yes, but you don’t have the time to wait for it.
A Longer Answer
Alongside the shining sun, budding plants and the renewed optimism that always follows winter, spring inevitably brings with it a storm of bloodthirsty fleas. If you notice a single flea in and around your home, it’s time to act before the hidden eggs hatch, metamorphose and start biting. When the store shelves are stacked high with poisons and so-called natural remedies, it’s worth a few moments’ thought to decide the most effective course of action.
Firstly, a little zoology: fleas live about 50 days and can lay over 2000 eggs in that time[1]. Assume 10% live to adulthood; you’ve got 200 little beasts that can jump several inches through the air. You need to kill off the adults and take care of the larvae to keep you and your pet free of nasty bites. Since your fleas almost certainly hitched a ride in on your unsuspecting pet, they are usually your first line of defense. A few combative options are:
- Bathing and combing your pet
- Deep cleaning your bedding and flooring
- Using flea repellents
If you’re committed to exterminating fleas from the home you should employ each of these ideas. Since we’re answering a specific question however, let’s turn to the tub.
Bathing With Fleas
As we said, fleas do drown. However, they are small enough that it can take up to several days for it to happen[2]. The reason is that their minute size allows them to sit on the water’s surface like a wolf spider, patiently waiting until the water drains. When bathing your pet, add some soap to the water: it will reduce its surface tension and force the fleas to slip beneath the waves.
Like when you had head lice as a child, the dreaded “flea comb” can be an ally against fleas. Methodically folding a fine-tooth comb – like the Safari Flea Comb for Cats – through your pets’ wet fur will pick up many fleas and larvae, which you should drown or squeeze immediately to be safe. Leave the water standing a while then thoroughly drain the tub, scanning the sides and bottom for survivors.
Once fleas have gained a foothold in your home, eradication requires some patience and systematic cleaning. While a tiresome process, it will surely be worth the reward. If you react early and your pet accepts a bath with minimal fuss, a little soapy drowning will do you a world of good.
To give an abridged long version: yes they will drown, but some soap and a careful grooming will significantly increase their casualty rate.
Sources
[1] https://adelaidevet.com.au/pet-library/fleas-solving-a-flea-problem
English 
German 
French 
Spanish 
Italian 
