ECA Steep Slope Development Relief

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 legal structures or pavement is located, not including landscaped or graded areas, and there is no increase in impact to the steep slope or buffer (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 an active landslide hazard, and the work is the minimum necessary for stabilization

• Tip 327A, Environmentally Critical Areas Exemptions, Relief from Prohibition on Steep Slope Development, and Modifications to Submittal Requirements

• Seattle Municipal Code section 25.09.090B

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.

Relief from prohibition on steep slope development is not applicable for waterfront lots.

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 (the SDCI base fee)
• You must pay for one half hour of review when you submit your application
• You pay additional review fees prior to receiving our decision

• Fee Subtitle

How Long Does It Take?

We try to finish the initial review of the application within 2 weeks.

Steps to Apply

You must receive an ECA Steep Slope Development Relief decision from us before your intake appointment for a building permit or a master use permit. Your application for relief from prohibition on steep slope development must be part of a specific project. You must submit a preliminary application for your project and have a construction record number (6XXXXXX-CN) before you can apply for the ECA Steep Slope Development Relief. You will apply for the ECA relief under the construction record.

1. Start your application. Begin your preliminary application and request your exemption or relief online through your Project Portal. You will need to upload a site plan and any documents you have to support your application. Examples of supporting documents include a geotechnical report, topographic survey, historical street grade profiles, and photographs.
2. Schedule a pre-application site visit. You'll receive an email once we have added the pre-application site visit (PASV) fees to your project. (Most projects require a PASV.) After you have paid the fee, we will perform the inspection. Your preliminary application materials will be sent to other departments for their review and comment as part of this process.
3. Submit additional information. As we review your application, we may ask for additional information.