Rats are destructive, disease carrying critters and you don't want them anywhere near your home and certainly not inside.
Before you can rid your home of rats, you first need to identify where the rats are hanging out; no sense placing traps in the basement if they are in the attic.
A black light is known to detect urine and a small, hand held one would be practical in this instance.
After you have located where they are nesting, it is time to find and seal off any possible entry points into your home and garden; Remember a rat can get through an opening that is only a half inch wide.
Look for cracks in your house foundation or extra space where any wires or pipes enter your home.
Also checks along your baseboards, cabinets and other dark areas for holes, seal these holes with steel wool as it will cut the gums of the rats if they attempt to chew through it.
Rats have a tendency to chew through almost anything, so you need to seal off these potential entrance ways with cement, sheet meshing, or some heavy metal material.
For added protection add some shards of glass to wet cement to deter rats from getting in before the cement dries.
Rats are attracted to water and live in sewers and will follow the scent of food to the pipes that lead to your toilet.
If you find a rat in your toilet bowl; squirt some dishwater liquid directly into bowl, close lid, wait a minute or two and then flush.
A 'snap trap' is the best way to get rid of rats, use a little peanut butter spread over a cotton ball as bail it attracts better than a piece of cheese.
Rats are quick and have the ability to grab the bait and get away before the trap snaps; wrapping the bait with some dental floss will get stuck in their teeth and slow their attempt to escape.
The best place to put the trap is where you found holes or rat droppings, taking care to place it away from reach of children or household pets.
Rat poisons are not the best choice to get rid of rats inside as they will die in places that will be difficult for you to remove them, causing a nasty odor.
Also, you need to use a lot of poison because a little will only make them sick and keep them away from it in the future.