There are places like this set up in Vancouver, BC. They have medical staff, and have houses set up for heroin users, drinkers, huffers, rock smokers, etc.
At the heroin house they supply clean water, fresh needles, sterilized melting containers, and the nurses will help find the correct places to inject, so people don't kill themselves. They even have the drugs there to reverse drug overdoses, so that if somebody crashes, they can get the Narcan into them before they code. The gubment says it's way safer for the people on the street, the users, and everyone in general. Once you have your drugs onboard, they have rooms where medical staff watch over you to make sure you don't die, drug counselors are on staff, and security so nobody gets robbed of their next hit, or the twenty spot they got from the pawn shop for their mothers TV.