使用双配水系统（一个用于饮用水，另一个用于非饮用水）分配再生水是一种广泛接受的做法。再生水使用量增加的一些驱动因素包括优质水资源供应的减少、开发新水源或将劣质水处理至饮用水标准的成本上升，以及向环境排放废水的成本增加。M24为希望分配再生水的水系统提供了最新信息。本手册讨论了社区双配水系统的规划、设计、施工、运行、监管框架和管理，该系统包括分配饮用水和非饮用水的独立系统，主要来自专门用于此类双配水系统的再生废水。 第四版包含大量修订，最显著的是纳入了美国环保局2012年水再利用指南和2017年饮用水再利用纲要。本手册还包含了反映该领域进步的其他变化。

The distribution of reclaimed water using dual water distribution systems, one for potable water and the other for nonpotable water, is a widely accepted practice. Some drivers for the increasing use of reclaimed water include diminishing supplies of high-quality water resources, escalating costs for developing new sources or for treating poor-quality water to potable-water standards, and the increasing costs involved in discharging wastewater to the environment.M24 provides the latest information for water systems wishing to distribute reclaimed water. This manual discusses the planning, design, construction, operation, regulatory framework, and management of community dual water distribution systems, which consist of separate systems for distributing potable water and nonpotable water principally drawn from reclaimed wastewater specifically for use in such dual distribution systems.This fourth edition contains considerable revision, most notably the incorporation of the USEPA 2012 Guidelines for Water Reuse and 2017 Potable Reuse Compendium. Additional changes that reflect advancements in the field have also been incorporated throughout the manual.