Waste Water Cuts Fertilizer Use

The effluent created by household sinks, washing machines and showers, known as gray water, could provide a new, low-cost source of irrigation for landscape plants that cuts down on the amount of fertilizer required to maintain them. The nonprofit Water Environmental Research Foundation’s (WERF) new report shows that many plants used for landscaping benefit from the use of gray water (Tinyurl.com/graywaterreport).

The study looked at seven homes in Arizona, California, Colorado and Texas with new and longstanding gray water systems that recycle wastewater to irrigate outdoor plants. Although the soil irrigated with gray water showed higher levels of cleaners, antimicrobials and sodium compared with areas irrigated with fresh water, there was enough nitrogen present in gray water to reduce or eliminate the need for additional fertilizers.

Not all plants responded positively, but WERF Communications Director Carrie Capuco says, “Gray water can be successfully used with the right plant choices.” Guidelines include heavily mulching the area where gray water is supplied to minimize contact with pets.