For The Answer
By Calvin Finch, Ph.D., Director of Conservation, SAWS, and Horticulturist
Submitted to Primetime Newspapers
To reduce the need for golf courses, Universities, the Botanical Garden and other large landscapes to use potable water to water their grass, SAWS is providing treated recycled water for the purpose. You have probably seen the purple pipes being placed around the City.
When the entire system is completed the reuse water system will provide about 20% the volume of water that the potable system supplies. This will make potable water available for other uses. So far the San Antonio Botanical Center, Trinity University, USAA, San Antonio Riverwalk and the Municipal Golf Courses are utilizing reuse water for landscape irrigation.
Homeowners also have an opportunity to recycle some of their water. It is legal to use gray water in San Antonio as long as it does not leave your yard or puddles (form pools). Gray water is defined as water from your washing machine. At this time shower water and dishwater is not allowed. Gray water works well for most plants. The modern soaps do not seem to be major sources of phosphates, and with 30 inches of rain per year on average, San Antonio has sufficient leaching volume to flush the materials. As a precaution move the gray water hose around the yard if you can.
Sometimes it is easy to drain the washing machine water directly into the yard. The drain hose can go into a plastic pipe that leaves the house through the wall where you connect a hose or more pipes. In other situations the help of a plumber may be required.
The typical washing machine uses 50 gallons (20 gallons less for a more efficient model) per load and is used for 3-4 loads per week. The 200 gallons per week could keep a 320-sq. ft. area green all summer. That would be a typical side yard. Every little bit helps.
Other sources of recycled water in your home include the condensation from your air conditioner, water softener flush water, and swimming pool flush water.
The condensate from your air conditioner is very high quality water. If the air conditioner is in your attic use a hose to transport the water to the landscape. For an air conditioner outside, collect the water in a pail to water your container plants or just run it out on the yard.
Water softener flush water can be salty but it is usually suitable for lawn grass, especially if you move the hose around. Natural rain will leach the salt before problem results.
In terms of volume at one time the water used to backwash a swimming pool can be significant. Applied to the lawn it can replace a whole weeks irrigation for a large area. Pool water does have chlorine and other chemicals to contend with ,but the infrequency of its availability and the volume of our rainfall usually address any negative impact. It is probably not a good idea however to apply the pool water over and over again to fruit trees or other sensitive plants.
If you have rain gutters it is relatively easy to collect enough rainwater for your container plants. Place a 55-gallon food quality drum under a shortened drainpipe and it will fill up with every rain. Rainwater is very high quality for watering plants. It is naturally acidic and can contain beneficial nutrients like nitrogen and sulfur.
It is possible to water an entire landscape with collected rainwater if you have enough storage tanks to supply water in between rains in the summer. For a copy of a rainwater harvesting guide send a letter to SAWS entitled Rainwater Harvesting. Inside include a self-addressed 8 ½ by 11 inch manila envelope. SAWS will mail you the guide.