Critical Areas, Stormwater, and Clearing and Grading Ordinances (CAO)

• Adopted ordinances 
• How does the CAO affect me? 
• Fact sheets 
• Questions and answers 
• CAO educational presentations 
• User's manual 
• Best available science 

Adopted ordinances

King County's updated Critical Areas Ordinance ("CAO") went into effect on January 1, 2005.  March 2009 update:  See questions and answers regarding Court rulings on King County's clearing limits in the CAO for recent developments.

The CAO has been incorporated into the King County Code. The King County Code is available online at www.kingcounty.gov/council/legislation/kc_code.aspx. The CAO has been codified as follows:

• Critical Areas--KCC Chapter 21A.24 (PDF*, 236KB)
      - King County Basin and Shoreline Conditions Map (PDF*, 1.3MB)
      - King County Critical Aquifer Recharge Areas Map (PDF*, 2.9MB)
• Stormwater--KCC Chapters 9.04 and 9.12 (PDF*, 246KB)
• Clearing and Grading--KCC Chapter 16.82 (PDF*, 657KB)

How does the CAO affect me?

King County has developed informational materials at different levels of detail to assist property owners, builders, consultants, and the general public in understanding the provisions of the CAO:

• Fact Sheets briefly describe the different elements of the CAO and its provisions to different types of critical areas and in different situations.
• Answers to Frequently Asked Questions.
• A PowerPoint slide show presented at a Permitting Department CAO Workshop provides a general overview of the entire CAO.
• The CAO User's Manual provides detailed information on the CAO in a more easily understandable format to assist property owners and permit applicants in understanding how the CAO will be applied.
• Best Available Science provides background information that was used by King County in developing the CAO.

Fact sheets

• Agriculture (PDF*, 82KB)
• Aquatic Areas (PDF*, 104KB)
• Clearing and Grading (PDF*, 77KB)
• Forest Management Plans (PDF*, 71KB)
• Horse Owner Information (PDF*, 97KB)
• Rural Properties - Fixed Standards (PDF*, 104KB)
• Rural Stewardship Plans (PDF*, 73KB)
• Urban Properties (PDF*, 100KB)
• Wetland Considerations (PDF*, 109KB)
• Wildlife Habitat (PDF*, 86KB)

Questions & answers

• List of Questions and Answers about the CAO (PDF*, 68KB)

CAO educational presentations

the Permitting Department has presented free workshops on the Critical Areas Ordinance. For those unable to attend, the workshop is available for viewing online, on KCTV, or by DVD. See DDES Workshops and Events for more information.

A PowerPoint presentation from the CAO workshop also is available in the following formats:

• View CAO PowerPoint Slide Show.
• Open or download CAO PowerPoint file (PPT*, 4.6 MB).
• View CAO PowerPoint presentation in PDF format (PDF*, 3.3 MB).

CAO user's manual

Introduction

• Introduction / Purpose of User's Manual (PDF*, 19KB )
• Table of Contents (PDF*, 182KB)

Part One - Administration

• Alterations and Alteration Exceptions (PDF*, 60KB)
• Agriculture (PDF*, 170KB)
• Rural Stewardship (PDF*, 28KB)
• Forest Stewardship (PDF*, 37KB)
• Critical Areas Designation (PDF*, 25KB)

Part Two - Critical Areas

• Coal Mine Hazard Areas (PDF*, 21KB)
• Erosion Hazard Areas (PDF*, 19KB)
• Flood Hazard Areas (PDF*, 741KB)
• Landslide Hazard Areas (PDF*, 22KB)
• Seismic Hazard Areas (PDF*, 19KB)
• Volcanic Hazard Areas (PDF*, 20KB)
• Steep Slope Hazard Areas (PDF*, 34KB)
• Critical Aquifer Recharge Areas (PDF*, 38KB)
• Wetlands (PDF*, 302KB)
• Aquatic Areas (PDF*, 282KB)
• Wildlife Habitat Conservation Areas (PDF*, 206KB)

Part Three - Surface Water

• Drainage Review and Requirements (PDF*, 66KB)

Part Four - Clearing and Grading

• Clearing and Grading (PDF*, 46KB)

CAO User's Manual as one document (entire file, PDF*, 2.1MB)

Best available science

Volume I: Review of Science Literature

• Title and Table of Contents (PDF*, 229KB)
• Chapter 1: Introduction (PDF*, 197KB)
• Map of Unincorporated King County Major Land Uses (PDF*, 1.8MB)
• Chapter 2: Scientific Framework (PDF*, 155KB)
• Chapter 3: Flood Hazard Areas (PDF*, 299KB)
• Chapter 4: Channel Migration Zones (PDF*, 199KB)
• Chapter 5: Geologic Hazard Areas (PDF*, 286KB)
• Chapter 6: Critical Aquifer Recharge Areas (PDF*, 281KB)
• Chapter 7: Aquatic Areas (PDF*, 872KB)
• Chapter 8: Wildlife Areas (PDF*, 631KB)
• Chapter 9: Wetlands (PDF*, 539KB)
• Appendix A: BAS Rule (PDF*, 142KB)
• Appendix B: Stormwater (PDF*, 716KB)
• Appendix C: Science Experts (PDF*, 260KB)

Volume II: Assessment of Proposed Ordinances

• Title and Table of Contents (PDF*, 133KB)
• Chapter 1: Introduction (PDF*, 52KB)
• Chapter 2: Assessment of CAO Fixed Regulations (PDF*, 234KB)
• Chapter 3: CAO Planning Programs and Incentives (PDF*, 221KB)
• Chapter 4: Assessment of Stormwater and Clearing & Grading Ordinances (PDF*, 81KB)
• Chapter 5: Institutional Context (PDF*, 69KB)
• Chapter 6: Conclusion (PDF*, 68KB)
• Appendix A: The Effects of Agricultural Operations on Critical
  Areas (PDF*, 219KB)

Literature References

• Best Available Science - Literature References (PDF*, 325KB)

*Note: To view PDFs, free software from Adobe is required. PowerPoint documents require Microsoft software.  See helpful hints for assistance.

To request this information in alternate formats for people with disabilities, call 206-296-6600 or TTY Relay:  711.