In general, residents of age-restricted retirement communities must be at least 55 years old, according to the Government Publishing Office. At least one person in 80 percent of the occupied units must be over 55 for these communities to maintain their age-restricted status.
Up to 20 percent of units can be occupied by people younger than 55, notes the American Bar Association. After the community is built and the units sold, responsibility for maintaining the occupancy ratio transfers from the developer to the tenant board. These boards admit new tenants, grant individual waivers and allow automatic waivers for widows and widowers younger than 55. If at any time fewer than 80 percent of the units are occupied by someone over age 55, the community loses its age-restricted status.