Rats are nocturnal and adaptable, so you must first find where they are active.
Install metal door sweeps, cover vents with mesh, and seal gaps around utility lines and pipes. 3. Sanitation (Remove Survival Resources)
Sealing entry points is the most essential long-term step to prevent a comeback.
Use chew-proof materials like stainless steel mesh (1/4-inch), steel wool (packed tightly with caulk), or concrete. Avoid using only expanding foam, as rats can chew through it.
If rats can't find food or water, they are less likely to stay. How To Get Rid of Rats - Busy Bins