The 1971 Environmental Rights Amendment to the Pennsylvania Constitution at Article I, Section 27 created individual rights to clean air, pure water, and other environmental features as well as a public trust in the Commonwealth’s public natural resources. Judicial interpretation significantly narrowed Section 27’s reach until the Pennsylvania Supreme Court’s Robinson Township decision in 2013 reinvigorated the Amendment. In the aftermath of Robinson Township, government officials and courts will need guidelines for how to comply with Section 27 in making and reviewing government actions and decisions. This article develops a set of concrete, practical principles for applying Section 27. It explores the meaning of Section 27 based on the text, Robinson Township’s analysis, and principles from private and public trust law. It articulates three concrete principles for the process of applying Section 27 revolving around the need for Pre-Action Assessment of environmental effects, whether direct or indirect and immediate, short- or long-term. It then articulates three concrete principles to guide the substance of Section 27 application. It concludes that commitment to the use of these procedural and substantive principles can provide a road map for Section 27 application that is true to the meaning and import of the Environmental Rights Amendment.