ECA Steep Slope Development Relief

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What Is It?

We restrict development on steep slopes. Steep slopes are slopes that rise at least 10 feet high over a horizontal distance of 25 feet or less. You are not allowed to develop in steep slope areas or their buffers, which are typically 15 feet wide.

We will allow development in the steep slope or the buffer area if your project is one of the following four types:

  • The proposed development is located where existing development is located and there is no increase in impact on the steep slope (e.g. you are replacing a structure with a building of the same size in the same location, with no increased impact on the steep slope)
  • Your proposed development is on a steep slope that was legally created by grading, and it was not a steep slope before the grading (e.g. the slope is a road cut)
  • Your proposed development site is an isolated steep slope less than 20 feet in height and at least 30 feet from other steep slope areas
  • Your proposed work is necessary to stabilize a landslide-prone area, and the work is the minimum necessary for stabilization

If we approve your application for relief from our prohibition on steep slope development, your site is still considered an environmentally critical area (ECA). This means that your project will go through ECA review as part of your master use permit or building permit application.

How Much Does It Cost?

The fee for your application is based on how long it takes us to complete the review:

  • We charge an hourly review fee
  • You must pay for one half hour of review when you submit your application
  • You pay the remaining review fee prior to receiving our decision

How Long Does It Take?

We try to finish the initial review of the application within one to two weeks.

Steps to Apply

You must receive an ECA Steep Slope Development Relief decision from us before you apply for a building permit or master use permit. Your application for relief from prohibition on steep slope development must be part of a specific project. You must complete a pre-application site visit before you submit your application.

  1. Fill out the Request for Relief from Prohibition on Steep Slope Development Form
  2. Attach any supporting documentation as needed (e.g. site plan, survey, geotechnical report, wetland report, and SDOT street grade profiles)
  3. Turn in your application at the Public Resource Center, located on the 20th floor of the Seattle Municipal Tower
  4. You do not need an appointment


What Do You Want To Do?

Still Need Help?

 Ask Us

  • Call us at (206) 684-8850
  • Visit the Public Resource Center
    700 5th Avenue, 20th floor
    M, W, F: 8:00 a.m. - 4:00 p.m.
    T, Th: 10:30 a.m. - 4:00 p.m.