as carla wohl us, the systems can cost from 100 bucks to many thousands. >> reporter: after an environmentalist ed begley jr. is practicing what he preaches, recycling the water he uses to wash up to also water his garden. he is installed what is called a gray water system. instead of going into the sewer, water from his bath, shower and laundry is pumped through an elaborate of filters. >> it takes out a lot of hair and lint and particles. >> if goes through coal and past a uv light to kill bacteria. before the water is stored in had been underground holding tank. how clean is this water, then? >> i'm sad to say it's probably cleaner than 50% of the world's population drinks. so i'm not going to drink it but i use it in my corn, tomatoes and fruit trees. >> the average american uses about 100 gallons of water a day. as much as 80% of that is gray water. water all the more precious in regions hard hit by drought. art has been teaching people how to install gray water systems for 20 years. he says they don't have to be expense you've. >> you can install a laundry to landscape gray water system y