I have a very long time customer who is going to build their dream home in Dallas. This is going to be the ultimate environment friendly home. Anyway they called me for expertise on putting a cistern under their garage to harvest rainwater to use in the automatic sprinkler system. Since I will end up taking care of this system I need to know everything about this. Two requests: Can anybody steer me to a site that explains this and if you are or know a local contractor who has expertise in this area please contact me.