Greywater use in the backyard: What are the health risks?

In 2006, strict restrictions on using tap water for gardening or car-washing were imposed in Melbourne but relaxed in 2010-2011 as rainfall replenished depleted reservoirs. During this five-year period residents collected their own greywater from washing machines and laundry, showers, baths, and kitchens. The problem with this is that people with diarrhoea and gastrointestinal illness might soil bed linen or clothes, or have an accident in the bathroom, and inadvertently transfer pathogens into the greywater. The worst-case scenario is that greywater containing infectious pathogens is used to water lettuce in a way that transmits infection to those eating unwashed leaves. The Environmental Protection Agency of Victoria (EPAV) published Guidelines (2008) designed to minimise harm to health or the environment. This research examined 1621 households and concluded that although half knew the guidelines existed, they were not following the advice, but nevertheless, although this study was limited, there appeared to be no significant increase in gastrointestinal illness. This research recommended that future housing design incorporate integrated water management strategies to enable safe greywater collection.