Heat and rising water levels flush the rats out of their hovels deep underground and force them to look for nests closer to homes. When incoming waters force them through the sewers Rodents keep moving, sometime right past the trap and into toilet bowls. Sealing vents, windows, garage door gaps, structural gaps and floor drains can keep rats from entering home or commercial business building. Smaller rats can fit through holes as large as a quarter in diameter.
Mice and rats generally inhabit the areas of the home least frequented, such as crawl spaces and attic insulation where they have access to food sources and moisture, and where they can build nests to begin reproducing.
A picture taken by our rodent exterminators in a crawlspace showing years of damage from rats and mice on a heat pipe that directs air to the house.