The purpose of this guidance manual is to provide technical information for water systems and states to assist them with complying with the Stage 2 Disinfectant and Disinfection Byproducts Rule, the Long Term 2 Enhanced Surface Water Treatment Rule, and other Safe Drinking Water Act (SDWA) regulations. This guidance is not a substitute for applicable legal requirements, nor is it a regulation itself. Thus, it does not impose legally binding requirements on any party, including EPA, states, or the regulated community. Interested parties are free to raise questions and objections to the guidance and the appropriateness of its use in a particular situation. Although this manual describes many methods for complying with SDWA requirements, the guidance presented here may not be appropriate for all situations, and alternative approaches may provide satisfactory performance. The mention of trade names or commercial products does not constitute endorsement or recommendation for use.