The feeding systems for anaerobic digestion facilities at wastewater plants in North America have been and continue to be modified and upgraded for a variety of reasons. These reasons include operational problems and issues, evolution from prior primary-sludge-only digestion facilities, performance-based reasons, regulatory-based reasons, and include the desire to improve the digestion process, the digested biosolids product, and the overall cost-effectiveness of the digestion process. Examples of methods agencies have used to improve their digestion feeding systems are described to explain some of the key ways in which agencies are making these modifications.