How to Kill Fleas on a Concrete Floor

The tiny black specks leaping onto your legs are a clear sign that there are fleas in the basement. No pets? No problem — you're warm-blooded, and that's enough to attract the pests. Whether you're killing fleas on a concrete floor or a carpet, the steps are essentially the same: Treat the pets and then vacuum, clean, spray, and repeat every two weeks until they disappear from your home.

Fleas are tiny, blood-sucking insects that jump onto you and your pets. The most common flea found in the home is the cat flea (​Ctenocephalides felis​). Like other flea species, the life cycle of the cat flea is simple: egg, larva, pupa, and adult flea.

While the cycle is simple, one element defines the persistent nature of a flea infestation. If there are no food sources, the flea won't emerge from the pupa until it senses movement and body heat. That's why you may find fleas in a basement when no pets or humans have been in the building for up to nine months.

To kill the fleas infesting your home, garage, and/or basement, first treat the pets. Effective flea treatments that are recommended by most veterinarians include topical "spot on" treatments applied to the back of the neck monthly and pills that are administered monthly or every three months. These flea treatments disrupt the flea life cycle by preventing the eggs and larvae from maturing, thus eliminating the fleas. The treatments are not interchangeable; do not use a dog medication on a cat or vice versa.

Once the pets have been treated, vacuum the entire house. While fleas usually hide in bedding and carpets, they can also hide in the cracks and crevices in and around hard surfaces, such as the concrete floor in your basement. Pay special attention around the edges of the basement where the walls meet the concrete and under and around any mechanicals, expansion joints, and holes or cracks. Consider using a shop vacuum to ensure you pull out as many of the creatures as possible from their hiding places.

Put the contents of the vacuum in a trash bag and put it in the trash outside. Next, mop the concrete floor with a cleaner/degreaser or other hard surface cleaner to pick up and remove dust, flea feces, eggs, and larvae missed by the vacuum cleaner. Rinse the floor with water and allow it to air-dry.

Put on a dust mask, safety goggles, and gloves and then spray the basement with a flea spray, again paying particular attention to any spaces where the tiny fleas can hide. You can also sweep a small amount of food-grade diatomaceous earth (DE) across the concrete and into the spaces around the walls to dry up and kill the fleas. Diatomaceous earth for fleas can be sprinkled outside around the outer walls of the house, but it must be kept dry to be effective against fleas inside and outside of your home. In addition, use DE with caution, as it can irritate your nose, throat, and eyes. Keep it out of the reach of children and do not use DE directly on your pets.

As tempting as it may be, an insecticide fogger, commonly known as a bug bomb, is not effective with fleas. When you set the bug bomb, the particles of the insecticide go up into the air and then settle on every surface in the room. However, the insecticide is not actually a "fog" and does not reach into the tiny cracks and crevices where the eggs, larvae, pupae, and adult fleas are hiding. Also, the active ingredient of the insecticide, usually pyrethrin, is not as effective against fleas.

Pyrethrin products are highly toxic to fish and cats and can affect humans who suffer from asthma and other respiratory issues. In addition, the accelerant in the fogger may be flammable. An open flame, even a cigarette, can cause a fire and in some cases, an explosion.