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The City of Portland, Oregon

Development Services

From Concept to Construction

Phone: 503-823-7300


1900 SW 4th Ave, Portland, OR 97201

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Rainy Season Construction Site and Erosion Control Measures


September 6, 2017

Rainy Season Construction Site and Erosion Control Measures

During the rainy season, between October 1st and April 30th, ground-disturbing construction work requires an elevated level of attention. Wet weather site and erosion control measures are necessary throughout the City. Additionally, there are area-specific locations in which ground-disturbing work between October 1st and April 30th is either limited or prohibited entirely.

Area-specific Limitations: Ground-disturbing construction work is prohibited between October 1st and April 30th within the Balch Creek and Forest Park Subdistricts of the Northwest Hills Plan District.

Exposed earth is required to be covered and stabilized no later than October 1st. All construction activity which exposes soil to stormwater, including sewer, water and utility trenching, must stop during this seasonal prohibition on ground-disturbing activities. If you have questions, please call the Planning & Zoning section of the Bureau of Development Services at 503-823-7526.
General Requirements: Projects in other areas of the City must comply with Title 10 Erosion Control Regulations. In most cases, construction activity may continue, but wet weather erosion control measures are required between October 1st and April 30th, including logging daily inspections of erosion control measures and providing temporary ground cover on exposed soils and stockpiles. A few additional requirements to note include:

  • All site development, construction, and demolition sites are required to post the Erosion Concerns Hotline signage at a location that is readable from the public-right-of way.
  • You must complete an erosion control inspection log and have it available onsite. 

The rainy season is a great time to brush up on your erosion control knowledge. Take time to review the City’s Erosion and Sediment Control Manual and plastic sheeting detail for stockpiles, or download them for quick reference on-site. If your construction team would benefit from erosion control training or a refresher course, check with these or other training providers: 

  • Northwest Environmental Training Center (
    • CESCL: Certified Erosion and Sediment Control Lead Training
    • Re-CESCL: Erosion and Sediment Control Lead Re-Certification
  • Southwest Washington Contractors Association (
    • Erosion Control (CESCL) Certification

To learn more about the Bureau of Development Services, visit us online at


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