Federal Building Clean Jobs Act of 2021 This bill establishes additional energy-efficiency requirements and programs for federal buildings, with a particular focus on reducing energy and water consumption and greenhouse gas emissions by FY2030 through partnerships with the private sector. Specifically, the bill requires federal agencies to reduce the following for their facilities by FY2030: average building energy intensity (by at least 25%, relative to FY2018); average potable water consumption intensity (by 54%, relative to FY2007); industrial, landscaping, and agricultural water consumption (by 20%, relative to FY2018); and specified categories of greenhouse gas emissions (by at least 40%, relative to FY2018). Federal agencies must also implement retrofit projects that reduce the energy consumption of their facilities by at least 35%. Additionally, the General Services Administration, the Department of Defense, the Department of Homeland Security, and the Department of Veterans Affairs must develop plans that ensure that at least 50% of certain facilities offer zero-emission vehicle charging or fueling by December 31, 2030. The bill directs agencies to work with the private sector through partnerships and financing opportunities in order to implement the bill's requirements. The bill also makes several other changes relating to federal building standards and related authorities, including (1) requiring lessors (i.e., property owners) to disclose data on the utility consumption of leased spaces; (2) requiring federal agencies to assess and mitigate area flood risks, based on climate science; and (3) authorizing long-term contracts for federal purchases of renewable energy.