Group Flood Insurance Policy Extension Act of 2019 This bill extends the term of certain existing Group Flood Insurance Policies. Specifically, the term is extended for active policies awaiting funds from the Department of Housing and Urban Development's Community Development Block Grant-Disaster Recovery fund. (Group Flood Insurance Policies are offered through the Federal Emergency Management Agency (FEMA) to certain individuals who do not have flood insurance and have received FEMA assistance after a presidentially declared disaster.) FEMA must provide financial assistance to individuals with extended-term policies in the amount of the additional required premium. The Government Accountability Office must report on the costs and benefits of Group Flood Insurance Policies and the rate at which individuals purchase private policies after the term of these policies expire.