Almost all the water that has ever existed on our planet is the same water we see today, 97% of which is nonpotable sea water. The remaining 3% of this water is freshwater, most locked in ice caps, glaciers and the ground. Only a fraction of a percent is the surface water we typically depend on. To put it in perspective, if all of the earth’s water were condensed down to fit into a single gallon jug, the freshwater readily available for our use would equal about one tablespoon. As the world population continues to increase so does the demand on this finite freshwater resource.

One ancient and low impact technique for obtaining freshwater is rainwater harvesting. This collection method is making a resurgence, aided by increased awareness of sustainability and new green building practices. Methods for collecting rainwater have been successfully used by our ancestors for thousands of years. To summarize the process, a large impermeable surface such as a roof initially “catches” rainwater. The rainwater is then diverted away from a catchment surface by gravity and a network of gutters, pipes or tubing, eventually ending up in a protected tank or cistern. This stored freshwater may be used over time, as needed, for either potable or nonpotable needs. With as little as 1” of rainfall on a 2,000 ft2 roof, 1,250 gallons of water could be harvested. For most locations in the US and Canada, tens of thousands of gallons of freshwater can be harvested by a typical family size residence annually.

Common Questions
• Are there regulations in place for the construction of rainwater catchment
systems and the usage of the water they collect?
• How is the quality of the collected water ensured, especially if intended for
potable use?

For more information, contact us at 877-ULHELPS or waterquote@ul.com.


RESOURCES