PA DEP eMapPA and Water Quality Database

Pennsylvania's official interactive environmental data mapping tools including integrated water quality monitoring results and impaired waters.

PA DEP's eMapPA is the state's interactive environmental data portal, bringing together dozens of data layers on water quality, impaired waters, wells, Act 537 plans, waste facilities, and regulatory actions. The related Water Quality Assessment and GIS Integrated Environmental System (WQUAL) provides detailed monitoring results from DEP ambient stations. These tools are essential for evidence-based watershed work in Pennsylvania. Users can query by HUC watershed, stream name, county, or municipality. Monitoring data includes water chemistry, macroinvertebrate bioassessments, and stream use attainment determinations. Watershed groups use DEP data to prioritize restoration targets, support grant applications, and document water quality changes over time.