SIERRA CLUB. says we don't. They want you to install rain barrels to take a bath and plant wildflowers on your lawn instead of grass. They say you waste water. I find that accusation insulting. Others say the only way to control building is to limit the future supply of water for your kids and GRANDKIDS but the OSC says we need an additional supply. Mixed messages but my opinion is that they should keep their dirty unwashed hands off my GRANDKIDS water supply.