Sanitation. Poor sanitation and the presence of garbage help rats to survive in residential areas. Good sanitation will effectively limit the number of rats that can survive in and around the home. This involves good housekeeping, proper storage and handling of food materials and refuse, and elimination of rodent shelter (harborage). Outside dog pens must be properly maintained to reduce potential rat problems. Removing clutter around homes allows inspection for signs of rats. Good sanitary practices will not eliminate rats under all conditions, but will make the environment less suitable for them to thrive.
The most successful and permanent form of rat control is to "build them out" by making their access to structures impossible. Ideally, all places where food is stored, processed or used should be rodent-proof. Store bulk foods, bird seed, and dry pet food in metal cans with tight-fitting lids.
Seal any openings larger than 1/4 inch to exclude both rats and mice. Openings where utility conduits enter buildings should be sealed tightly with metal or concrete. Equip floor drains and sewer pipes with tight-fitting grates having openings less than 1/4 inch in diameter. Doors, windows and screens should fit tightly. It may be necessary to cover edges with sheet metal to prevent gnawing.