How to Shine a Light on a Bowl of Water to Catch Fleas

Place a lamp on the floor. Leave the light on or use a night light with the cover removed as your light source. Purchase a flea trap with a light programmed to turn off and on at regular intervals or connect your light to a timer set to turn the light on for 10 minutes then off for 5 seconds for a more effective trap. The University of Florida IFAS Extension notes that adult-stage fleas are triggered to jump toward light when it is interrupted by shadow. A yellow-green light is most attractive to fleas, according to the extension.

Fill a bowl with water and add a few drops of dish liquid. Fleas will fall into the water when they jump toward the light. Fleas cannot swim. When coated in the soapy water, they will not be able to jump out of the bowl. Place the bowl beneath the light or adjust the fixture to train the light to shine toward the bowl.

Set your trap overnight in a room commonly used by pets or a room where you suspect fleas are living. Exclude you pets and small children for safety reasons if you cannot monitor their behavior.