Ensuring the energy and water efficiency of federally subsidized multifamily housing would reduce operating costs, increase building longevity, and offer health and affordability benefits, in addition to reducing carbon emissions. Despite these benefits, several barriers prevent retrofitting from scaling, including the lack of a sophisticated capital market system and regulatory impediments. This paper recommends a variety of HUD initiated actions that will reduce regulatory barriers, promote a capital market that incentivizes retrofits, and cultivate a cross-silo funding stream.