Managing water in Pennsylvania is undergoing significant stress right now- due to floods, droughts, contamination, and water quality concerns. This talk explores the legal structure of water law in Pennsylvania—both for water quantity/allocation and water quality—with a particular focus on groundwater issues. We will briefly touch on the interstate and regional nature of water management through various interstate compacts such as the Delaware River Compact and regional agreements such as the Chesapeake Bay total maximum daily load.