Government agencies often require environmental risk mitigation strategies to pass a cost-benefit test. All else equal, these favor protection of valuable assets, which can produce inequitable outcomes. We demonstrate that distributional equity in efficient risk mitigation is influenced by how efficiency is operationalized and propose an alternative efficiency measure which better satisfies egalitarian and prioritarian equity notions. We compare optimal allocations of $100 million to home elevation projects in New Orleans, that minimize flood risk measured in (i) dollars or (ii) as a proportion of a structure’s replacement cost. Minimizing the latter metric allocates more resources to impoverished neighborhoods. It reduces proportional damage to residences by an additional 11% at the expense of 2% of economic damages. Composite strategies show even more favorable tradeoffs (4% proportional damage for 0.04% economic damage). This demonstrates the power of equity-aware efficiency measures in improving distributional outcomes.