This reader built a rain-catcher cistern, and he uses his collected rainwater to water his lawn.
After reading your article "Harvesting the Rain" (August/September 2003), I wanted to describe the cistern I built 13 years ago to catch the rain falling from the eaves of our house. I made a 4-foot-tall, 8-by-12-foot box out of 2-by-20-inch planks. I lined the box with plywood, then lined this box with a 16-by-20-foot plastic tarp. I replaced the tarp after 10 years, even though it was not leaking. I use a siphon and pump to tap into the water, so the liner has no openings.
The cistern has a cover made of 2-by-6-inch lumber to keep the sunlight away from the liner and, so far, it works great. The cistern cost about $500 to build and it holds 2,700 gallons, which has been enough to water the garden every year since I built it.
Cary, North Carolina