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The City of Portland, Oregon

Portland Water Bureau

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Customer Service: 503-823-7770


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Rainwater Resources

Using Harvested Rainwater Outdoors vs. Indoors

Harvested rainwater is often used for outdoor irrigation, such as watering a lawn or garden. In Portland, you are not required to get a city building permit to harvest rainwater and use it outdoors if harvested rainwater is intended for gravity-fed irrigation only and the system is completely separate from the municipal water system. Other requirements, such as backflow assembly installation and inspection, electrical permits for any pumps installed, a plumbing permit and/or a grading permit for underground pipe installation, may be necessary depending upon system size and complexity.  

Most rainwater harvesting systems in Portland designed for indoor water use are for nondrinking water uses such as flushing a toilet. If thinking about harvesting rainwater for limited, residential indoor use, follow the relevant Code Guide for rainwater harvesting available through the Bureau of Development Services.

Learn about local plumbing code requirements for harvesting rainwater by reading the specialty plumbing code: Chapter 6: Rainwater Harvesting Systems for Interior Use or Combined Interior and Exterior Use.

Rainwater harvesting systems can play a part in on-site stormwater management. Handling stormwater on your property by disconnecting downspouts, building rain gardens, or installing rain barrels can help reduce combined sewer overflows (CSOs), increase groundwater recharge, and reduce pollutants in surface waters. Rainwater harvesting systems can also be used during new construction or redevelopment to address stormwater management requirements and to help projects meet green building certifications.

The Bureau of Environmental Services has a variety of publications available to help Portlanders manage stormwater. Visit the Sustainable Stormwater section of their website for more information.

When you manage stormwater runoff on you property you can qualify for a discount of up to 100% of the on-site stormwater charge that appears on your water bill. Learn more about Clean River Rewards by visiting or by calling 503-823-7740.

  • Portland Water Bureau

Rainwater harvesting systems that incorporate the use of pumps to create a pressurized system require a backflow assembly be installed on the water service to the property. This excludes systems that simply capture rainwater in a container and gravity-feed to the landscape. See City of Portland Water Code Backflow Assembly Installation Requirements Page 3, Item 6, for more information.

Additionally, the Portland Water Bureau offers information and technical resources to all customers about using water efficiently and cost effectively. Contact the Water Efficiency Program at 503-823-4527 or visit for more information.


Download a brochure on Rainwater Harvesting here.