Seal Holes and Cracks
Another way fleas may be entering your home is on the backs of tiny little mice, moles and other vermin. Especially if you live in an older home, there very well may be some small cracks and holes along the foundation where a mouse might get in the house. Get a can of spray foam and make your way around your house, checking every nook and cranny for cracks and holes. You'd be surprised at how small a crack can be and still accommodate a mouse or a rat. Make sure you get everything sealed up and this will help keep pests at bay.