Where are fleas commonly found?
Keeping this in consideration, where do fleas live in the house?
Fleas' ideal living conditions are in a humid, moist and dark place where they can feed on organic material or blood from mammals. They can be founded in tall grass, in shrubs, weeds, wood piles, debris, a dog's house, a shed or a garage, outdoors furniture, and any other moist areas.
Simply so, where are all the fleas coming from?
Fleas are often found in the yard, especially in areas where an animal sleeps on a regular basis. This is a very common place to find flea larvae, in fact. As your pet sleeps outside, he will allow the adult fleas to drop flea dirt into the soil, and feed the flea larvae.
Fleas do not hibernate, and they do not become inactive in the winter. Since fleas are opportunistic, they're going to ride pets into the home and hunker down for the cold season, since their sole purpose is to feed and repopulate. (Fleas cannot survive in freezing temperatures so they're not about to try to leave).