Save Affordable Housing Act of 2021 This bill revises the low-income housing tax credit to repeal the qualified contract option for a building that received its allocation of housing credit dollar amount before January 1, 2019, or received before that date, a determination from the bond issuer or housing credit agency of its eligibility to receive an allocation of a housing credit dollar amount. Under current law, properties eligible for the low-income housing tax credit are subject to a 30-year affordability period, during which the value of properties is set at a below market rate. The qualified contract option allows property owners, in some cases, to convert to market rate after 15 years.