Rats are nocturnal creatures that live in colonies and require both food and a water source. Outside nests are often found alongside housing foundations near walls. Often, rats forage inside of homes for food and return to their outside burrows, while at other times they set up camp right in your home. Rats breed quickly, are unsanitary and can cause destruction to indoor wiring and walls. Once you kill a rat, the best way to keep another from coming back is to seal off all entryways used by the rodents.
Inspect your home with a flashlight for signs of rat activity to discover how they are getting in and where to place traps. Signs of rat activity include black smudging on walls, urine and rat droppings, tracks, and signs of gnawing. Begin your inspection from the outside, working your way indoors. Pay special attention to doorways, windows, thresholds and drain spouts.
Purchase traps to kill your rats, as they are safer than poison baits, are quick and provide immediate results. Disposal is also easier and more sanitary, as often rats crawl off to inaccessible areas to die when poisoned. You'll be able to smell a poisoned rat, but you probably won't be able to get to it.
Do not set the traps immediately when placing them around the home--but do bait them with large dollops of peanut butter. Rats are wary of new objects, and allowing them to acclimate to the traps while getting used to feeding off of them will allow you a higher and more assured kill rate.
Place traps around the areas you noted from your visual inspection. If there are a number of rats in the home, you will want to set close to a dozen traps, while large commercial buildings should use a minimum of two to three dozen. Leave the traps in place for several days to a week to allow the rats to get used to them.
Set traps carefully, as the spring on them could break your finger. Be sure not to place them in areas where children or pets can access them. Bait them and carefully pull back on the spring lock mechanism to set them to kill.
Check the traps in the morning or when you hear one go off for a quick disposal. Carefully remove the rat from the trap if you plan to reuse it, or throw the entire trap away in a plastic bag placed immediately outdoors in your dustbin. Wear rubber gloves when touching the trap and wash your hands thoroughly after handling it.
Seal up any openings into your home greater than 1/4 inch wide. Access points are often near where utility lines enter the home, air conditioning openings, vents and drain pipes. Check for broken windows in your basement, or warped doors or those with spacing underneath. Stuff copper mesh around utility lines, pipes, dryer vents, and telephone and cable wires. Check the shingles on your roof to ensure they are tight, and secure any roof vents and flashing. Clean up garbage inside and outside of your home, in addition to trimming back vegetation and foliage around the house.