Home Lead Safety Tax Credit Act of 2021 This bill allows owners of eligible dwelling units a new tax credit through 2024 for 50% of the lead hazard reduction activity costs for each such unit, up to an aggregate of $4,000 per unit. An eligible dwelling unit is any unit located in the United States that was placed in service before 1978. The bill (1) specifies the types of lead hazard reduction activity costs eligible for the credit, including risk assessment and abatement costs; and (2) limits the amount of the credit in any taxable year to $3,000 for specified abatement measures and $1,000 for interim lead control measures.