Canadians are some of the highest per capita users of water in the world. Yet simple changes to water use habits and household equipment can reduce water consumption in the home by up to 40%. There are many things we can do to help reduce water use. Some are quite common, simple and inexpensive, whereas others are relatively new or ground-breaking. One that fits into this latter category is using reclaimed water.
Household reclaimed water is wastewater from residential sources such as sinks, bathtubs, showers, washing machines and toilets that is treated and reused for beneficial purposes (e.g., toilet flushing). The use of household reclaimed water can make significant contributions to reducing unnecessary water use. However, household reclaimed water must be treated and managed effectively as there is a potential health risk to users, particularly from pathogens that can be responsible for severe gastrointestinal illness. From government at all levels to individual community members, we all have a role to play in ensuring the safe and sustainable use of reclaimed water.
The most effective way to ensure that household reclaimed water is used safely is to become aware of the types of hazards that may impact reclaimed water and adopt appropriate strategies to manage these hazards. The aim of a risk-based approach is to identify all of the potential hazards in a reclaimed water treatment system, assess their potential impact on water quality and on public health, and find ways to mitigate those risks rather than simply react when problems occur. This concept is similar to the Multiple Barrier Approach used in the management of safe drinking water supplies. Knowing what the risks are and how to manage them is an important way to ensure that we can safely use reclaimed household wastewater.
In 2004, the Canada Mortgage and Housing Corporation (CMHC) approached Health Canada regarding the development of guidelines for household reclaimed water in response to the growing interest in water conservation. Based on this proposal, the Committee on Health and Environment (CHE) agreed to establish a Working Group to prepare "Canadian Guidelines for Household Reclaimed Water". CMHC provided the funding for this project. Although the long-term goal is to develop comprehensive guidelines to allow the safe use of reclaimed water for many beneficial purposes, the focus of this first version of these guidelines is limited to the specific end use of toilet or urinal flushing.
The primary objective of establishing guidelines for reclaimed water is to ensure that the operation of water reclamation systems is protective of public health. Consequently, this document provides guidelines for reclaimed water quality, as well as guidance on potential elements of a management framework (Part I) and an overview of the scientific basis for the guidelines (Part II). It recommends possible elements of a management framework that are applicable to on-site or decentralized treatment of household wastewater for reuse in residential or commercial toilet and urinal flushing.