Compilation of State-Level Freshwater Harmful Algal Bloom Recreational and Drinking Water Guidelines for the Conterminous United States as of 2022

This data release contains a national compilation of state-level qualitative and quantitative guidance for a variety of environmental indicators that are used to identify the presence of a harmful algal bloom (HAB) in freshwater ecosystems. These include qualitative guidelines based on visual or olfactory signals, as well as quantitative guidelines based on cyanotoxin concentrations, algal biomass density, and chlorophyll a concentrations. Many states in the United States have adopted guidelines based on recommendations from the U.S. Environmental Protection Agency or the World Health Organization. However, a few states have also developed their own guidelines. We are specifically focused on fresh, inland waters and we compiled guidance related to recreational and drinking water use. This data release provides guidance that is publicly available via state webpages. Additionally, states may have internal guidance and/or guidance may be available at the county or local level. This data release provides national-scale information about the indicators and associated thresholds that water resource managers use to protect humans from the potential negative effects of HABs. Note, state guidelines were queried during the summer of 2022. The attached zipped folder, State_webpages.zip, contains html and pdf files of the state webpages and posted documents used to compile the information in this data release.