Surveys of surface waters in North America and Europe have contributed to an understanding of the nature of the resources and of impacts from air pollution. Some recent, statistically based surveys provide quantitative estimates of chemical and physical properties of populations of lakes. In the absence of abundant, high-quality, historical lake chemistry data, surveys have been used to evaluate the extent and magnitude of acidification. One can infer changes in lake chemistry by using spatially extensive lake chemistry data over a range of geological and hydrological lake response types and varied deposition patterns. We report here on the results of a probability survey of lakes that was designed to examine some of the issues relevant to surface water acidification and lake surveys designed for other purposes.