Rainwater Harvesting on the Pedernales

Rainwater Harvesting on the Pedernales

Bill and Donna Davis moved into their new Hill Country home in October of 2002. The Davis' came to this area in part to be near children and grandchildren in Austin and in part because of the quiet and beauty of the area.



When they came they brought an appreciation for the preciousness of water. Bill, retired from the petroleum exploration business, had become involved in water issues in another water-challenged area, the Colorado Rockies, and understood how easily many can take that resource for granted.



After a few years on Blanco County groundwater and drawing on his geological background to better understand just how precious our groundwater resources are, Bill became interested in rainwater harvesting. Bill attended a Preserve Our Water education session on rainwater harvesting and soon after the Davis' made the decision to move ahead on their own rainwater system.



In a household with a scientist and attorney, detailed research was a given. Once satisfied with the various elements of the system the Davis' contracted for the installation. Bill worked closely with the installer and invested a good bit of sweat equity in the project. The final installation was completed in time to capture some of the wonderful rain that fell during the summer of 2007.



The Davis' system features fiberglass tanks. While more costly than the common plastic tanks, the longer expected life span of the fiberglass over plastic was the deciding factor. The fairly standard two stage particle filtration and UV lamp installed on the outside wall of the basement prepares the water for potable use.



With a collection surface of 5,650 square feet, the system can capture between 3,100 and 3,500 gallons per inch of rainfall. The water is stored in four 4,000 gallon main tanks, located under the main floor deck, and in a stand alone 5,000 gallon tank located down hill near the guest house. Gravity and a 1 inch flexible pipe allows for transfer to the guest house tank. Another filtration system provides potable water for visitors to the guest house.



As can be noted in the photograph of the front of the home, it is not at all evident that a rainwater system is present unless one goes to the rear of the house. Only a very small part of the PVC used to connect gutters to the tanks is visible, except from the rear. In that photo the PVC carrying water from the front gutters is just visible as it emerges from underground. Because the main tanks are next to the basement wall where the filtration components are located, little in the way of visible plumbing is required.



The Davis' are quite pleased with the quality of the water, a dramatic improvement over the groundwater on which they had relied since 2002. They also enjoy a sense of water security that rainwater harvesting so often brings.