Do flea larvae drown in water?


Flea larvae quickly drown when exposed to free water. And when soil moisture rises above 20%, the larvae die within 24 hours. Water also dissolves the adult flea feces in the environment, which the larvae depend on for nutrition.


Flooding & Irrigation

Outdoors, flea larvae develop in shaded, moist areas. However, they’ll quickly drown in a flooded environment. Rainwater or irrigation water from sprinklers can kill larvae in poorly drained areas. In addition, the water will dissolve adult fecal blood, which the larvae need for food.

It’s thought that fleas are most abundant in summers with slightly above average rainfall. But, in summers with heavy rainfall, flea populations are at their lowest numbers.

Soil Moisture

Flea larvae can survive in a soil moisture between 1-20%. Mortality drastically increases once above 20% Fig 1. The larvae live within two centimeters of the soil’s surface. When soil moisture exceeds 10%, the ground becomes saturated and gas exchange gets blocked. As a result, the larvae move to the surface. As soil moisture increases beyond 20%, a film of water develops on the surface and the larvae drown.

Sandy Clay
Silty Clay

Fig 1 Percent of flea larvae that survive after 24 hours (y-axis) in different increments of soil moisture (x-axis), in three soil compositions.


Flea larvae are sometimes raised in jars for research. On warm days, they can end up drowning from condensation accumulating on a jar’s glass surfaces.


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  • Karen July 4, 2016, 5:54 pm

    Hi, I love all your graphs, although can I make one suggestions. As in the graph above, for the three soil types, could the color of the text for Sand, Sandy Clay, and Silty Clay (shown in upper left corner of graph) be changed to match the color of the line graphed which it corresponds too.

    Just wondering which line graph is for Sand. Is it the gold, red or orange graph?

    Thank you,

    • Adam Retzer July 6, 2016, 9:25 pm


      I’ll definitely make those changes to make it more readable. Currently I am redesigning the site, and it’s throwing some things off. The graphs are one of those things. I apologize for the confusion. I hope to get it resolved soon.

  • Catherine October 19, 2016, 5:24 pm

    I have been fighting a flea problem (infestation) for 7 months. Thought problem started March 2016 but neighbor said her dogs had fleas about September- October 2015. Therefore I have many cocoons which are pesticide resistant. I have samples of the fleas that I need to have assessed. Please if anyone can help, in identifying type of flea as these are not cat fleas!

  • Pamela Penner November 14, 2017, 12:42 pm

    So grateful to have found this site.
    You provide a wealth of info.
    Thank you!