Emergency Flood Response Act This bill directs the Federal Emergency Management Agency (FEMA) to establish and carry out a pilot program to assist flood response efforts at state and federal regional levels in response to a levee failure or potential levee failure. FEMA may award grants to up to 10 eligible entities to: (1) establish or maintain a flood emergency fund, and (2) ensure a unified command system organizational framework for emergency flood activities. An "eligible entity" is a levee maintaining agency or unit of local government that is responsible for emergency flood response efforts. Funds awarded under this bill may be used for emergency flood activities, including prompt emergency action to prevent levee failure, close levee breaks, make relief cuts and dewater flooded areas, and otherwise physically limit the extent, depth, and duration of flood waters in the event of a levee failure. Funds awarded may not be used if the emergency flood activity is required by law to be performed by the Corps of Engineers and the Corps immediately exercises its authority. FEMA shall ensure that, following an expenditure of funds from a grantee's flood emergency fund, the grantee will seek all available state and federal disaster assistance reimbursements for such expenditures and deposit the reimbursements in the fund. The federal share of the cost of a flood emergency activity carried out using grant funds made available under this bill may not exceed 50%.