Before the advent of today's municipal water treatment facilities, many people relied solely on the collection of rainwater for household, landscape and agricultural uses. In some parts of the world, such as Bermuda, the U.S. Virgin Islands and even parts of Australia, people still depend on rainwater collection systems to meet most of their water needs.

Even in communities where many residents are supplied with public water for drinking, homeowners and businesses are turning to rainwater collection systems to meet non-potable water needs, such as landscape watering, especially in dry regions.

When collecting rainwater for drinking water, it's important to use materials and components that have been tested for their safety in such applications. The NSF Rainwater Catchment System Components program establishes testing guidelines for products such as roofing materials and coatings to confirm that they do not impart contaminants into the water at levels that exceed U.S. Environmental Protection Agency (EPA) health guidelines.

In addition to rainwater system components, many of the storage tanks and plumbing fixtures used to store and transport rainwater can also be evaluated under NSF/ANSI/CAN 61: Drinking Water System Components to verify that these products also meet current public health standards for contact with drinking water.

A list of NSF-certified components for both rainwater catchment system components and water distribution system components is available from the NSF online product database.