Build the Wall Now Act This bill resumes the construction of, and modifies the requirements for, a physical barrier along the U.S.-Mexico border. Specifically, the Department of Homeland Security (DHS) must, within one day of the bill's enactment, resume any project related to the construction of such barriers (and any related infrastructure), and DHS may not cancel any contracts related to such construction that were entered into on or before January 20, 2021. Additionally, funds already appropriated for such construction must remain available until expended. The bill also modifies the requirements for the physical barriers along the southern border and requires DHS to consult with the labor organization representing border patrol agents about the safety and effectiveness of the agents deployed in the vicinity of the barriers. Finally, the bill exempts these construction projects from certain legal requirements, including requirements stemming from the Administrative Procedure Act, the Clean Air Act, the Clean Water Act, and the federal laws regarding public contracts.