Rainwater Harvesting: Oregon Smart Guides from the Building Code Division Part III

By Law Clerk Lincoln Herman

“Rainwater Harvesting”

These are systems designed to capture water that runs off the roof of a structure. Under Oregon Law you may only capture the water that runs off of your roof in one of these systems. The purpose is to create a store of water that can be reused both in and outside of the structure. For example, water collected in a rain barrel may be reused for gardening. Also, water collected in a cistern system may be filtered.

There is a large volume of water that may be collected from a roof. For example, a home near Portland with a footprint of 2,000 square feet has a runoff of just over 39,000 gallons per year. All of that water may be captured and reused. The national average for household water usage is 127,400 gallons per year. Accordingly, a reduction in fresh water usage of almost one third is possible.