Graywater Use for Bermudagrass (Cynodon dactylon) Lawns.

As the world population increases, the amount of finite potable water will become more valuable.  In order for turfgrasses to be used in the landscape for utilitarian and aesthetic purposes, alternative water sources will need to replace precious potable water. One method is to reuse graywater from individual households into home landscapes.  Graywater is the water collected from the household sink basins, clothes washers, and showers; but does not include kitchen sinks, toilets, and dishwashers.  The objectives of this research are: 1) to measure turfgrass growth and quality when irrigated with graywater, 2) to identify the potential potable water savings, and 3) to monitor soil quality changes.  The research study site is located at New Mexico State University in Las Cruces, NM.  The graywater is collected from an adjacent mobile home that is passed through a filtration system and then applied to a landscape through a subsurface drip irrigation system.  Turfgrass quality is measured by plant density and uniformity through treated and control plots.  Water savings are calculated on a weekly basis, by keeping the evapotranspiration (ET) rate at 80%, and supplemented with potable water to maintain the 80% ET rate.  Quarterly soil and water samples are taken to determine overall additions of nutrients from the water to the soil profile.  The results to date show less than a 10% increase in sodium levels with insignificant levels of surfactant accumulation.  A 5% increase in nitrate levels in the soil has also been recorded. The weekly average household production of 1135 liters provides 25% of the water requirements for 93m² of turfgrass and 25 landscape plants.  The application of graywater to turfgrass is showing it to be a viable alternative to using only potable water applications.