Things get more complicated if you're planning to drink, wash, or bathe with rainwater. You need specific types of roofs, gutters, and storage tanks, as well as a way to filter and purify the water and pump it into your house.
Filter can take out most bacteria and particulates, and reverse osmosis will catch the sulfuric and nitric acids in acid rain. Unfortunately, there are areas with such heavy air pollution that rainwater cannot be filtered enough to make it drinkable.
"If you live in a highly industrialized area, I recommend using rain for gardening only," cautions Bill Hoffman, a coordinator for the city of Austin Water Conservation Program, in Texas. "If you have any concern about rain quality, have a professional water test done on a sample."
Shown: The writer uses rainwater for all her household needs. The 39,000-gallon system consists of three 11,000-gallon fiberglass tanks and two with a capacity of 3,000 gallons each. Located 150 feet from the main house, a 900-square-foot shed (which also collects rain) helps hide two of the 10-foot-tall tanks from view.