The police officer at your door may sound very confident that he or she can do anything at all regarding a home search, but that's not always the case. You have certain protections that limit what the police can actually do within your home. This counts for a house or an apartment.
It is very important to understand some of these limitations. A few key examples include:
1. Protective sweeps
Police can usually look through your home during an arrest to see if you are alone. The goal is to look for an accomplice and keep themselves and the public safe. That does not mean they can tear your home apart, looking anywhere they want. For instance, they may be able to look in a bedroom closet because someone else could theoretically have hidden inside, but they cannot use the same logic to look in a bathroom medicine cabinet.
In most cases, police do have to get a warrant before they come into your house. They may knock without one and ask your permission, and they can come in if you grant it, but you can legally turn them away. They then have to go and get a warrant before coming back and forcing their way in. Ignoring this order of events can mean that evidence they find cannot get used in court. There are special exceptions to this rule, such as if they think you are destroying evidence or if they think a crime is actively happening.
If you have a "legitimate expectation of privacy," that's when the police need a warrant. This is what protects your home or apartment. It does not extend to any property you own. They can sit in their car and look over your front yard without breaking any laws. But they cannot come inside, because you have a right to expect privacy within the house. If the public can't see it, neither can police.
You may worry that police will lie and try to trick you into allowing the search. What if they tell you they have a warrant when they really do not, for instance, and then you tell them to come in? If they do this, the police have broken the law. They cannot trick you into allowing them to enter the home. If they do, evidence could get thrown out of court. The only way for you to legally allow the search is to voluntarily and freely give them permission to come in.
If you think that the police violated your rights, you need to know what steps you can take. Remember that all American citizens have these protections during every search.