scope:

Introduction

Since 1983, when the first edition of this American Water Works Association (AWWA) manual was published, many water and wastewater utilities, communities, authorities, states, and countries have implemented dual water distribution systems, particularly in light of the increased emphasis on higher degrees of wastewater treatment. These water-reclamation facilities can significantly increase the availability of reclaimed water for use as described in this manual. They provide reclaimed wastewater to a variety of customers, making the most of all their available water resources. The International Water Association in London lists, in addition to the United States, Australia, and the United Kingdom, 13 other countries that have strong programs in dual water distribution and water reclamation. Assessing the growth of water reclamation and the adoption of dual water distribution systems for communities large and small has been a difficult task as their growth seems to be almost exponential. What is appreciated worldwide is that wastewater reclamation and dual water distribution systems are an important consideration for communities as they search to expand their water supply resource(s).

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. Increasingly, there is the potential for potable reuse, which is discussed in various locations throughout this manual. Reclaimed water treated to potable-water standards is not distributed in a dual distribution system.