Its common knowledge, or at least should be, that if you are allowing drug activity to go down on your property, you may have your assests seized by the federal government. Car, house, land, bank accounts, etc..anything that can be considered ill gotten gains from the illegal activity. This is a civil action and does not require a criminal case.
Like it or not, right or wrong, drugs are still illegal, and allowing it on your property is not a good idea.