Lead-Safe Housing for Kids Act of 2021 This bill requires the Department of Housing and Urban Development (HUD) to issue regulations regarding lead-based paint in certain federally assisted housing that was constructed prior to 1978 and in which a child younger than age six will reside. Specifically, HUD must require owners of such housing to (1) conduct, within specified time frames, risk assessment for lead-based paint hazards; (2) control the hazards; and (3) provide certain notice to residents. If a family with a child younger than age six occupies such housing in which lead-based paint hazards are identified but not controlled, HUD must allow the family to relocate on an emergency basis to another dwelling without any wait, penalty, or lapse in assistance.