Federal Flood Management Act of 2018 This bill directs executive agencies, including military departments, to reduce the risk of flood losses, minimize flood impacts, and restore and preserve natural floodplains. Agencies must also: (1) evaluate the effects of an action taking place in a floodplain, (2) ensure planning programs and budget requests incorporate flood hazard considerations, and (3) indicate their compliance with this bill to the Office of Management and Budget when making a request for a new authorization or appropriation. The bill sets forth characteristics to be used in determining whether an agency action impacts a floodplain. The Mitigation Framework Leadership Group must reassess annually the implementation of these requirements, and provide recommendations to the Water Resources Council. An agency undertaking a federally funded project must comply with federal flood risk management standards, including construction guidelines, flood-proofing measures, and elevation techniques. Projects may be exempted if compliance would not be in the interest of national security, a project is in response to an emergency, or the standard is demonstrably inappropriate. An agency facilitating a financial transaction in an area subject to a base flood (a base flood has a 1% chance of being equaled or exceeded in any year) has a duty to inform any private party of the hazards. Agencies must report on their compliance with this bill to the Council on Environmental Quality.