Water conservation is a major focus of LEED guidelines, and the standards that you follow when certifying your home include several different ways to qualify for points for water recycling and conservation. One option for conserving water is harvesting rainwater. By installing systems of troughs and barrels to collect runoff from the roof, you can use rainwater to water plants in the yard, or even for drinking (once it's been filtered). You can also qualify for points if you install a gray water recycling system in your house [source: U.S. Green Building Council]. Gray water is non-potable water leftover from clothes washers, sink drains and showers that isn't safe for human consumption [source: Barker]. Like harvested rainwater, you can use it to irrigate outdoor plants, or install a system that recycles gray water to make it potable. Both of those solutions win LEED certification points. Those systems can be expensive to install, but you can make up for the cost through long term savings in utility bills. Some regions of the country even have their own municipal gray water systems. Hooking up your home to one of those systems can qualify it for certification points, too [source: U.S. Green Building Council].