Programs that provide financial assistance and supportive services that stabilize households in their current housing or help them to move into new housing without first entering the shelter system or experiencing homelessness. Services may include financial assistance (short or medium-term rental assistance, security or utility deposits, utility payments, moving cost assistance), housing relocation and stabilization services, legal assistance (generally mediation), credit counseling and case management. The goal is to help households resolve their crisis, secure short-term financial or rental assistance as needed, and access ongoing sources of support in the community in order to remain housed. If the individual or family is unable to stay in their existing housing, the prevention program helps the household to find an alternative housing arrangement that is safe, reasonably affordable and adequate.

Programs that assign a staff member to assist people who are looking for housing to survey the available residences and to choose and obtain the most suitable option.

Programs that provide permanent accommodations for people who have a chronic problem with excessive use of alcohol and/or use of other drugs and no expectation of recovery. In most cases, there are no requirements for abstinence as a condition for housing. Included are "damp" housing for people who are able to live in a setting where abstinence is encouraged but substance use is permitted on the premises in moderation; and "wet" housing for people who are unwilling and/or unable to make a commitment to consumption limitations and are actively using drugs and/or alcohol addictively. In most cases, alcohol consumption is permitted at the residence, either in a person's room or in common areas, while drug use is not tolerated on-site but residents can use drugs away from the building. Both are contrasted to "dry" housing where residences are alcohol and drug-free. In most cases, residents in these facilities are formerly homeless and have undergone numerous failed attempts at treatment for alcohol and/or drug use. Without this harm reduction alternative, homeless people with chronic substance use issues sleep on the street and are at increased risk of exposure to adulterated or harmful substances, or depend on costly detoxification and scarce emergency shelter beds for housing.

Individuals who are generally between the ages of 18 and 25 depending on the ages that specific programs use for qualification.

A condition, previously referred to in the U.S. as "dual diagnosis", in which individuals have both a diagnosed mental illness and a substance use disorder involving either drugs or alcohol. Any combination of mental health and substance use disorders qualifies for this diagnosis, e.g., an alcohol use disorder and depression, post-traumatic stress disorder and a heroin use disorder, prescription drug dependence and anxiety. For purposes of treatment, it is recommended that clients receive intensive medical and therapeutic intervention and care for both disorders at the same time, allowing them to manage the symptoms caused by the mental health disorder without resorting to drugs and/or alcohol and worsening their mental health symptoms, or allowing an untreated mental health order to increase the urge to drink or get high.

Individuals and families who have no fixed, regular and adequate residence, who are residing temporarily with relatives or friends or who live on the street, in emergency or transitional shelters, in a hotel or motel paid for with a shelter voucher, in seriously substandard housing or in an abandoned building, place of business, car or other vehicle, or other public or private place that is not ordinarily used as a regular sleeping accommodation for people. Some people who are homeless have issues with substance abuse, chronic or severe mental illness, chronic unemployment or underemployment, or other problems that prevent them from obtaining housing.