|Wednesday Whatís New: Rainwater Harvesting and Your Roof|
|Written by Heleigh Bostwick Wednesday, 29 June 2011|
Although I donít live in Texas or in a place where water is scarce, todayís Daily Dirt looks at an issue that Iíve wondered about myself regarding roofing material and rainwater harvesting. In this case however, itís not related to watering the garden, but looks at harvesting rainwater for potable use.
The study was conducted by students and faculty at the Cockrell School of Engineering at The University of Texas at Austin and found that five roofing materials tested, metal (specifically Galvalumeģ), concrete tile and cool roofs produce the highest harvested rainwater quality for indoor domestic use. The study also showed that rainwater from asphalt fiberglass shingle roofs and increasingly popular "green" roofs contain high levels of dissolved organic carbon (DOC).
Water with DOC is not necessarily dangerous on its own, but Assistant Professor of civil, architectural and environmental engineering Mary Jo Kirisits, who headed up the study, said when it's mixed with chlorine -- a common product used to disinfect water -- the two substances react to form byproducts that potentially cause cancer and other negative human health effects.
While some roofing materials performed better than others in the study, Kirisits said rainwater harvested from each of the roofs would still have to be treated if the consumer wanted to meet EPA's drinking water standards or reuse guidelines.
The U.S. Environmental Protection Agency doesn't regulate the quality of residential rainwater collected through harvesting, but some local agencies and states, like Texas and Hawaii -- which are among the most proactive -- offer voluntary water quality guidelines.
Source: Rainwater Harvest Study Finds Roofing Material Affects Water Quality
Photo source: www.texasponds.com