Housing Supply and Affordability Act This bill allows the Department of Housing and Urban Development to award grants to states, local governments, Indian tribes, and Native Hawaiian organizations for the development and implementation of housing policy plans. These plans must increase the housing supply while avoiding resident displacement, increase housing affordability, and reduce barriers to housing development. The amounts provided by the bill are designated as an emergency requirement pursuant to the Statutory Pay-As-You-Go Act of 2010 (PAYGO) and the Senate PAYGO rule. (This excludes the budget effects from being counted for the purposes of enforcing the PAYGO rules.)