This document provides guidelines for the planning, design principles and considerations of a decentralized/onsite water reuse system and water reuse applications in urban areas.

This document is applicable to practitioners and authorities who intend to implement principles and decisions on decentralized water reuse in a safe, reliable and sustainable manner.

This document addresses decentralized/onsite water reuse systems in their entirety and is applicable to any water reclamation system component (e.g. source water collection, treatment, storage, distribution, operation and maintenance and monitoring).

This document provides:

— standard terms and definitions;

— description of system components and possible models of a decentralized/onsite water reuse system;

— design principles of a decentralized/onsite water reuse system;

— common assessment criteria and related examples of water quality indicators, all without setting any target values or thresholds;

— specific aspects for consideration and emergency response.

Design parameters and regulatory values of a decentralized/onsite water reuse system are out of the scope of this document.