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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

Rainy Season Construction Site and Erosion Control Measures

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

Area-specific limitations: Ground-disturbing construction work is prohibited between October 1 and April 30 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 1. 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 1 and April 30, 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