Kight Residence, Boerne (Spring 2008)
- Design Team: John Kight, Boerne, Texas
- System Location: 33 Tower Road, Boerne, Texas 78006-7921
- Capacity: 34,650 gallons in six 5,000-gallon and three 1,550-gallon cisterns
- Catchment Area: 6,400 square foot roof area
- Water Use: Potable and non-potable use
When the Kights purchased land to build their home in Boerne, they investigated the availability of water in the area and the cost to install a groundwater well. They discovered that groundwater in the area was hard and contained both iron and sulfur that would need to be treated before the water could be used. The cost to install a well would have been in excess of $26,000. Under these circumstances, they concluded that harvesting rainwater was a better option and rainwater would be their sole source of water supply.
Constructed in 2002, the Kight's rainwater collection system includes a 6,400-square-foot roof area, six 5,000-gallon, and three 1,550-gallon above-ground polypropylene tanks for collecting rainwater. Collectively, the tanks have a maximum holding capacity of 34,650 gallons. The system is almost entirely gravity-driven, except for a pump that is used to move water into the house.
Water collected from the roof initially passes through a double-weave sock filter to remove solid particles such as dust, leaves, bloom, and bird droppings. From there, water targeted for potable supplies is pumped through a 5-micron cloth filter, then through a 3-micron charcoal filter, and finally through an ultraviolet filter to kill bacteria. The resulting water is almost completely free of total dissolved solids (maximum concentration detected at 5 milligrams per liter). The Kights typically have the water tested by a laboratory twice a year. They also use the harvested rainwater to irrigate their lawn.
The system was designed and installed at a cost of $14,500. The annual maintenance cost is approximately $100, mainly for filters and ultraviolet lamp replacements.
The Kights are dedicated to spreading the word about the benefits of rainwater harvesting in the Hill Country and have conducted over 50 workshops and made numerous presentations to interested community groups. To date, over 1,000 individuals have visited their home to get a first-hand look at the system and taste the water.
Photograph courtesy of John Kight.
Note: Some of the information presented here was obtained from Tracy Hobson Lehmannn's article entitled Homeowners tap clouds for their water needs available online at http://www.raincatcher.org/2006_11_01_archive.html.