Posted August 17th, 2014

Graywater — how does it fit?


 Excerpted from an article by Doug Pushard 


What is graywater? It is the water that has been used by a household, except water from the kitchen sink and toilets. Water from these two sources is called black water and requires special treatment. The state publishes a terrific graywater guide that covers graywater uses and provides some wonderful diagrams of its capture and use. It can be found

It is legal in New Mexico to use graywater on your landscaping. No permit is required if the graywater produced is less than 250 gallons per day and certain guidelines are followed. At this time, it is neither legal nor recommended that you mix graywater and rainwater storage. It can be done with a permit, and the graywater will need to be filtered prior to storage. For most residences, this is apt to prove too expensive, but for commercial entities that produce a lot of graywater, it should be evaluated.

Graywater is better for our landscapes than regular drinking water. It has little to none of the chlorine left in it and is rich in nutrients. Graywater use on plants can also eliminate the need for fertilizers, thereby saving you money on both your water bill and gardening costs.

Graywater definitely needs to be part of our water conservation. Unlike rainwater, graywater is very consistent. It is generated every day and usually in a very consistent amount. The city of Santa Fe estimates that graywater accounts for about 40 percent of the water used inside the house.

If every household in Santa Fe could use graywater for irrigation, it would cut our summer water demand by nearly 20 percent!

Of course this is not possible. For existing houses, it would be difficult or prohibitively expensive to capture and reuse all 40 percent. However, if it were required for all new construction, then over time it would begin to have an impact on our water demand. If it was incentivized by the state, county or city for remodels, then even if only 10 percent of Santa Fe remodels captured 50 percent of the graywater from the houses, it would still have a significant impact on our potable water use for outside irrigation.

Graywater reuse is one of the alternatives being implemented in cities across the country, most notably in Tucson, Ariz. In that city, graywater reuse is required in all new homes.

Graywater use is one of several strategies necessary to maintain our future water security. Together with rainwater harvesting and moving to more drought-tolerant plants, we can go a long way toward having a secure water supply for generations to come.

Doug Pushard, founder of the website www.Harvest, has designed and installed residential rainwater systems for more than a decade. He is a member of the Santa Fe Water Conservation Committee, a lifetime member of the American Rainwater Catchment Systems Association and an EPA WaterSense Partner.

Source: The Santa Fe New Mexican.

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