Controlling rats is about population control and requires a coordinated effort in more than just your individual home. You will need to work with your neighbors and the city to effectively deal with the problem. If you lived on a farm, a barn cat might help control rodents. But in a city, forget about it. We have plenty of alley cats in my alley, and the rats still persist because, among other things, some of my neighbors are filthy pigs. So, what do you do?
– As others have said, seal all entry points into your house with rat proof materials – metals are great.
– Place poison baits all around the outside. They are inhumane, but you are trying to eliminate the rats, right? Killing is killing.
– Contact the city and have them come out and inspect the area – try to coordinate with them if possible
– Contact an exterminator or other animal control specialist. You want someone who understands rat behavior and habits and can intelligently approach the problem.
– Work with your neighbors so your combined area is rat unfriendly.
– Rat traps. Another potentially inhumane solution, but again, you want to eliminate them.
– Read up on rat behavior and prevention.
– Clean up outside and inside your house. Do not leave piles of leaves or debris or garbage anywhere. No newspaper piles or clothing piles or packed closets. Rats need nests – don’t leave them any.