General Grading & Drainage Requirements

​(Projects vested prior to September 30, 2010)


Restrictions Related to Critical Areas
  • Critical Areas: Channel Migration Zone Maps (SCC 30.62B.330)
  • Southwest UGA: Little Bear Creek Watershed (SCC 30.63C.025)
  • Serene Way: Frontage improvement standards
  • Lake Stevens UGA: Tightline systems are required (SCC 30.63A.225)
  • Lake Stevens UGA: Detention facility design requirements - Weiser Creek, Burri Creek, and Fox Creek basins (SCC 30.63A.226)
Outside Agency Requirements (Applicant's Responsibility)
All Developments
All new development must use adequate temporary erosion control Best Management Practices (BMPs). If developing in a floodplain, please contact the flood hazard specialist at 425-388-3311, extension 2731. If your development will occur within 300 feet of a FWHCA fish bearing stream, demonstrate compliance with SCC 30.62A.320(1)(c) and Rule 6225: Chapter 30.62A SCC Infiltration Standards.
Full Drainage Plan
Major development proposals (more than 5,000 square feet of new impervious surface area, or more than 5,000 cubic yards of gross cut or fill) generally require storm water detention and water quality treatment facilities designed by a professional engineer licensed in Washington.
Targeted Drainage Plan
Other developments (more than 200 but less than 5,000 square feet of new impervious surface area) generally have no detention or water quality treatment requirements. A Targeted Drainage Plan can either be for construction, or can be a conceptual plan usually associated with a land use action going to hearing. View the Targeted Drainage Plan Checklist.

Grading Plan
A grading permit is required for all grading that does not meet the exemption requirements of 30.63B. When no impervious surfaces are proposed but a grading permit is still required, use the Grading Plan Submittal Checklist.

Grading Application
Low Impact Development
Low Impact Development (LID) is now available for projects meeting LID Ordinance 30.63C, and is offered as an alternative. Use the 2005 DOE Manual if claiming credits in your detention pond sizing for using LID techniques.
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