The answer to 'how did extermination get in my house' is that there are several common ways pests can find their way into a home. Pests like rodents, insects, and other small animals are often attracted to food, water, and shelter that can be found inside a house. They may enter through cracks, gaps, or openings in the home's exterior, or even be brought in accidentally through items brought into the house.
Some of the most common ways pests get into homes include: gaps around windows, doors, or pipes; cracks in the foundation or walls; openings around utility pipes or wires; and being transported in boxes, bags, or other items. Pests can also enter through pet doors or holes chewed by other animals. Signs of a pest problem may include seeing the pests themselves, finding droppings, or noticing damage to food, furniture, or other household items.