The National Surface Water Survey represents a unique design for determining, with known confidence, the numbers and percentages of lakes and streams in large regions of the United States that have chemical characteristics that can be interpreted in light of present conditions, past damage, and future potential impacts of acid deposition. The Survey also provides a framework for interpreting future, site-specific intensive studies in a regional context. This paper describes the basis for this design, as well as some strengths and weaknesses of regional, as opposed to the more traditional single-system, approaches to lake and stream management.