The Fourth Amendment to the U.S. Constitution protects people from the government performing unreasonable searches and seizures and requires that warrants may only be issued based upon probable cause. So the general rule is that the police have to have a warrant to enter your home unless there is an exception to that rule and it is a reasonable search.
The Supreme Court has made exceptions to the warrant rule through several cases. The exceptions that allow police to enter your person or property without a warrant are as follows:
1. Search incident to lawful arrest – the police enter a home to make an arrest. They can search the immediate area of the arrest.
2. Plain Sight – Police are lawfully in a place where they can see evidence in plain sight. They can seize the evidence and it may give them probable cause to search further.
3. Consent – You allow the police to search your home.
4. Dangerous weapon – The police have reason to believe that you have a dangerous weapon which they fear may be used against them.
5. Automobile – if the evidence can be moved and never recovered while the police seek a warrant the police can search.
6. Exigent Circumstances or Hot Pursuit – If someone in the home is in danger or the police follow a person into a home while pursuing them for committing a felony.