The National Environmental Methods Index (NEMI) is a searchable database designed to help scientists and managers find and compare environmental monitoring methods, protocols, and procedures. It covers analytical and field methods across the phases of environmental monitoring, with a particular focus on the water-monitoring process. Users can search the full database by keyword or method number, or browse available methods and protocols.

Filtered search options help narrow results by analyte and method category, including chemical, microbiological, population and community, toxicity, physical, statistical, and regulatory methods. Additional filters address topics such as waterbody type, gear, matrix, complexity, analysis type, publication source, media, instrumentation, and method type. NEMI also provides supporting resources, including an introduction to the database, a glossary, frequently asked questions, and updates.

Researchers and other users can submit a method or contact the NEMI team. By bringing environmental methods together in a searchable format, the index supports informed comparison and discovery for people working with monitoring data and procedures