It depends on the situation.
If the police knock on your door, ask if they have a warrant. If the police can produce the search warrant signed by a judge, then it is usually best to let them in.
If the police do not have a warrant, then you usually do not have to let them in. If the police ask for your consent without a warrant, be sure to kindly say no. Note that if a homeowner gives police his/her consent to search, the police then no longer need a warrant to carry out the search.
Also note there are some "exigent" circumstances where police may lawfully search homes without a warrant. This occurs when either:
- The police have a reasonable belief that someone inside the home may be injured, or
- The police are in hot pursuit of a fleeing felon who just ran into your home