The answer to 'how did flea get in my house' is that fleas are commonly brought into homes by pets like dogs and cats. Fleas can also hitch a ride on clothing, furniture, and other items. Flea infestations often start small but can quickly grow as the fleas reproduce rapidly.
Some common signs of a flea problem include seeing fleas on your pets, finding flea dirt (flea excrement) on your pet's fur or in your home, and noticing your pet scratching and biting at their skin. Flea bites on humans are another indication that you have a flea infestation.