The best place to start is the Suppliers Roadmap to Zero. For wastewater testing specifically see the Wastewater and Sludge Guidelines chapter. There are also some useful frequently asked questions and answers on our Knowledge Base that my help. Additionally please check out wastewater specific training on our ZDHC Academy. Plus don't forget you can always ask Zeddy our AI chatbot available on the forum, website and Knowledge Base (bottom right corner)