Whether police need a search warrant for something like a garbage generally depends on whether you have a reasonable expectation of privacy in the place or thing being searched. When it comes to garbage, your expectation of privacy can depend on where the trash is located. If your garbage is awaiting pick-up in the alley, police will likely have a right to investigate. If your garbage was still within the curtilage of your home, however, police may first need a warrant.
Generally, police cannot enter a private residence unless they have emergency or exigent circumstances, consent or a warrant. The curtilage of your home is included in this Fourth Amendment protection. The curtilage is defined as the land immediately surrounding and associated with your home. The scope of the curtilage is generally determined by whether you reasonably expect the area to be treated like your home. For example, the area within your fenced-in yard would be a curtilage.
The case law in this area is complex and depends a great deal on the specific facts of each situation. Therefore, if your garbage is still in your garage or next to your back door, the police may require a warrant before they can poke through it. (However, if the police are otherwise lawfully within the curtilage of your home, and happen to see something in plain view, they can investigate the object.)
This protection regarding garbage applies even if you are a guest in someone’s home. Therefore, if you are staying at a friend’s and you throw contraband in their garbage, you have a privacy expectation up until the point when the garbage is set outside for pick-up.
***
This question was originally answered at skokiecriminallawyer.com. The author retains all copyrights.