2020 Census Accountability Act This bill requires the Bureau of the Census to establish the Task Force on the 2020 Census, which shall report to Congress on: existing and potential policies and measures that promote full participation in the decennial census by all residents of the United States; potential negative impacts on minority populations resulting from the addition of a citizenship question to the census, including potential impacts on congressional reapportionment, legislative redistricting, and distribution of federal funds; civil rights issues that could be affected with the addition of a citizenship question to the census; and a potential decrease in participation related to the addition of citizenship questions. The task force shall terminate following the 2020 decennial census.