When a person has conquered drug or alcohol addiction, it's not as easy as starting life again where you left off. Restoring a positive and happy life takes time and a great deal of hard work. A Halfway House, a.k.a. a Sober Living Facility, is a place where people in recovery can go where they can live in a sober and healthy setting until they are able to live confidently on their own. Living in a Halfway House may be a term of a person's probation or parole for example, or the individual might decide to live in a Halfway House of their own will after drug or alcohol treatment. In either case, occupants of a Halfway House are drug and alcohol free and working towards doing what they need to do to get their lives back on track. This could mean, for example, getting one's GED, finding a job, etc.
Halfway Houses in Sims are managed by people who in most cases were once residents of the house. The duration a person is allowed to remain at the Halfway House can vary, but it's typically anywhere from a month to a couple of years. Residents are required to submit to drug and alcohol testing prior to entering the house, and this testing will take place randomly to ensure there isn't any substance use in the house or substance abuse problems that would be more effectively dealt with in an addiction rehab facility.