Downspout Disconnection

Where soils soak up water and yards don’t have steep slopes, disconnecting your downspouts to direct water from your roof to your yard can be a simple, inexpensive, effective, and easy way to manage the rain on your property.
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What Is Downspout Disconnection?

Many Portland homes and buildings have downspouts or rain drains that send rain into the City's sewer and stormwater pipes. When you disconnect your downspouts, you help keep the rain running off your roof out of pipes to help prevent overflows and backups. Instead, the rainwater soaks into the ground on your property and helps your lawn or garden grow.  

Downspout disconnection is considered a “retrofit option” for existing buildings, generally meaning the property has been connected to the City’s pipes now or in the past. The information on this page is not for new development or construction. If you are unsure whether or not downspout disconnection is a solution for you, contact the Private Property Drainage Inquiries team to discuss your questions.  

How Downspout Disconnection Works

To disconnect your downspouts, there are four basic steps:

  1. First, make sure to secure the downspout to existing structures.
  2. Cut through the downspout.
  3. Plug or cap the sewer standpipe.
  4. Attach new downspout elbows and use extensions or a splash block to channel water away from the building.

Watch this video or download our printable How-To Guide below to get step-by-step instructions and see how simple this is.

Summary of Downspout Disconnection Requirements

Disconnection is simple, inexpensive, effective, and easily integrated into the landscape design. Below are the necessary guidelines to make sure you safely and effectively disconnect your downspouts while protecting people and property.


  • Add or remove soil to make sure the ground slopes and water flows away from structures.  
  • Do not disconnect downspouts onslopes greater than 10 percent.


  • Make sure you have enough landscaped area for rain to soak safely into the ground.  
  • The area of your yard where the rain will soak in must be at least 10 percent of size of the roof area that will drain to it. For example, to drain 500 square feet of rooftop, there should be at least 50 square feet of landscape to catch the water.


  • Disconnected downspouts should not allow roof runoff to drain or pool at the base of a building. Instead, use a downspout elbow and extension to direct the water away from a basement or foundation. Check the How-To Guide for details.
  • Safely discharge water:
    • At least 6 feet from a structure’s basement.
    • At least 2 feet from a structure’s crawl space or slab foundation.  

Property Lines

  • The end of your downspout extension must be:
    • At least 5 feet from your neighbor’s property line.
    • At least 10 feet from structures or buildings on any adjacent property.
    • At least 3 feet from the public sidewalk.  
  • You may need more room if your yard slopes towards your neighbor or the sidewalk allowing stormwater to cross the property line.


  • Avoid creating tripping hazards. Do not install extensions across walkways, patios, driveways, or in front of a gate.

Other Hazards

  • Do not direct runoff on top of a septic system, drain field, or an underground oil tank unless they have been decommissioned.  
  • Do not direct water to an area within 10 feet of a retaining wall.

When to Call a Professional

Most property owners can disconnect downspouts without help from professional. Property owners with questions about drainage issues or disconnecting the downspouts on their property can contact the Environmental Services Private Property Drainage Inquiries team.

Costs and Permits

Downspout disconnection is inexpensive. Materials are readily available at hardware, building supply, and home improvement stores.

A permit is not required to disconnect downspouts using an extension and splash block. If you plan to connect the downspouts to an underground solution like a drywell or soakage trench, see those pages for permitting information.  

Maintenance Requirements

Disconnected downspout maintenance is minimal.  

Periodic maintenance includes:   

  • Checking to ensure the discharge location has proper erosion control and drainage.  
  • Checking materials for leaks or defects. Most materials can last for about 10 years and can easily be replaced.
  • Regularly removing accumulated leaves or debris, especially from gutters, downspouts, and from the end of the downspout extension.  
  • Check to make sure water can safely drain and stay away from building foundations. Adding bark mulch or changes in landscaping can trap water against building foundations.

Stormwater Management Manual

Consult the City’s Stormwater Management Manual for the complete set of requirements on how to safely site, build, and maintain any stormwater management solution on your property.

Clean River Rewards Eligibility  

Residential and commercial property owners who install qualified stormwater management solutions may be eligible for discounts on the stormwater charges of their sewer, stormwater, and water bill through Clean River Rewards.  

Disconnected downspouts that meet the safety and space requirements outlined above may be eligible for Clean River Rewards. Visit Clean River Rewards to learn more. 


Private Property Drainage Inquiries

Environmental Services
phone number503-823-5858For questions from home and business owners about safe ways to manage the rain on their property or solutions to drainage problems.