Can your dog have fleas but not house?

It is unlikely that your dog would have fleas but your house would not. Fleas thrive in warm, humid environments, and they need a host to survive. While they can live in your house without your dog, it is much less likely, as they would need to find another animal to feed on. If your dog has fleas, it is important to treat both your dog and your house to prevent the fleas from returning.