How to best reuse residential greywater is addressed in the practical West Australian Greywater Guide published recently by the Greywater and Wastewater Industry Group (GWIG). Available free on-line (www.gwig.org), its target audience is developers, planners, architects, builders, and the general public.
GWIG is a not-for-profit based in WA which understands the frustration that many people feel when looking to reuse their greywater. Greywater reuse should be a straightforward way to keep gardens green whilst saving water.
The Greywater Guide provides a clear and practical step-by-step approach to reuse and includes information on its benefits; regulatory guidance; types of greywater systems and technology; application, landscape and irrigation considerations for implementation; design and technical considerations; indicative costs; installation and maintenance advice; water quality; use in regional areas of WA; and how best to include greywater in planning and design.
Case studies and working examples are interspersed throughout the guide to provide direction on greywater reuse considering the prevailing residential building market, retrofit, location, and regulatory constraints. In addition, and complementary to the guide, are the Residential Greywater-Ready Plumbing Guidelines which provide builders and plumbers with the technical information necessary to make new dwellings greywater-ready; a means of future-proofing housing stock.
Developers who incorporate greywater reuse into their projects will contribute towards Water Sensitive Urban Design (WSUD) outcomes through a reduced reliance on mains water for garden irrigation. In addition, projects may be eligible for credit towards sustainability rating schemes such as the Urban Development Institute of Australia’s EnviroDevelopment and the Waterwise Development Program, which promote best practice water efficiency and enhance urban greening and cooling.
Gardens and lawn play an important role in our urban environment including providing shade, passive cooling, privacy, habitat for birds and animals, soft surfaces for recreation and play, air quality benefits and many more. Replacing these with hard surfaces and artificial turf in response to water efficiency or water restrictions is counter-productive to a healthy neighbourhood – reusing our greywater can play a significant and water restriction-free role in sustaining these vital green spaces.
A recently published study in Perth demonstrated that direct diversion greywater systems reduced mains water use in the garden between 30% and 60% (Byrne et al., 2020).
With everyone’s support greywater reuse can be something Australia can proudly say it is utilising to its fullest capacity.
Reference: Quantifying the Benefits of Residential Greywater Reuse. Byrne et al., Water 2020, 12, 2310; doi:10.3390/w12082310.