Grading, Drainage, and Clearing Requirements (Land Disturbing Activity)

Why is regulation of stormwater runoff important?

Stormwater runoff is rain that runs off hard surfaces, rooftops, streets, parking lots, and landscaped areas. As water runs off these surfaces, it can pick up pollutants such as oils, dirt, and fertilizers. Polluted stormwater runoff is a leading contributor to water pollution in the Puget Sound region.


Runoff can also cause and contribute to flooding. When runoff is uncontrolled, it could result in the destruction of property, harm to fish and wildlife, damage to aquatic habitats, loss in aesthetic values, and cause threats to public health due to contaminated food, drinking water supplies, and recreational waterways.


Snohomish County is committed to complying with federal and state requirements to provide effective and efficient stormwater management in our community. As part of our work, we maintain stormwater regulations that guide new development and redevelopment to minimize pollution and harmful effects of stormwater.

Waterdrop2

Where can I find the County’s Stormwater regulations?

Please visit the Stormwater and Drainage Regulations webpage for more information on the permitting process and links to associated checklists and assistance bulletins.


The County’s current stormwater and drainage requirements are found in:


Please visit our LID webpage for resources and information.

Washington State Department of Ecology issued a new Phase I Permit in August 2019. The County is required to update its stormwater drainage program to reflect new Phase I Permit requirements by July 1, 2021.


What documents will be updated by the County?

  1. County Code in Chapters 30.63A and 30.63B SCC
  2. Snohomish County Stormwater Manual (Volumes I through V
  3. Snohomish County Engineering Design and Development Standards (Chapters 1, 5, and 11)

As documents are updated, they will be posted in this webpage (coming soon) for public review.

If you have comments related to the new Phase I Permit requirements and/or the associated updates to county documents, please submit your comments via email to the project manager.

Stormwater, drainage, and land disturbing activity regulations are updated from time to time. Generally, projects vest to a particular version of the regulations depending on when project applications are submitted. However, a recent Washington State Supreme Court decision and the County’s Phase I Municipal Stormwater Permit (“Phase I Permit”), issued to the County by the Washington State Department of Ecology, now require a different result.

Background

On December 29, 2016, the Washington State Supreme Court issued a decision in Snohomish County v. Pollution Control Hearings Board related to the County’s Phase I Permit. The Court held the County’s updated stormwater regulations are not “land use control ordinances” subject to state vesting statutes. This is a significant change in the law for developments across the state.

Snohomish County is a Phase I jurisdiction under the federal Clean Water Act National Pollutant Discharge and Elimination System (NPDES) program. The County must comply with its Phase I Permit. One aspect of the County’s compliance with its Phase I Permit is the adoption of updated stormwater drainage regulations, which the County accomplished effective January 22, 2016, and which the County must further update by July 1, 2021. County documents that will be updated by July 2021 include: Chapters 30.63A and 30.63B SCC, Snohomish County Drainage Manual (Volumes I through V), and Snohomish County Design and Development Standards (Chapters 1, 5 and 11). The current county stormwater program can be reviewed on the Drainage and Land Disturbing Activity webpage.


What Does This Mean for Development Projects?

The County’s Phase I Permit requires the County to impose updated drainage regulations to projects that have not started construction as follows:

  • Approved projects currently subject to a pre-January 22, 2016, version of the County’s drainage regulations that have not started construction by July 1, 2021, must be reevaluated by PDS for compliance with updated drainage regulations the County will adopt by July 1, 2021.
  • Pending applications submitted prior to January 22, 2016, that have not been approved and thus have not started construction by July 1, 2021, must be reevaluated by PDS for compliance with updated drainage regulations the County will adopt by July 1, 2021.

As used above, “started construction” is defined in the County’s Phase I Permit as: the site work associated with, and directly related to the approved project has begun. For example: grading the project site to final grade or utility installation. Simply clearing the project site does not constitute the start of construction.


PDS is preparing to implement this requirement effective July 1, 2021. PDS recognizes the Supreme Court decision and the requirements Ecology imposed on the County under its Phase I Permit may impact significantly some development projects, and is evaluating ways to facilitate the permitting process to minimize that impact while fully implementing the County’s obligations under its Phase I Permit. PDS performed a detailed review of its records, followed by hundreds of site inspections, to identify potentially impacted projects. PDS sent notices to alert applicants or permit-holders that may be impacted by the July 1, 2021, started construction deadline.

Contact Us

  • If you have questions about a specific application already submitted to PDS, please contact your project manager/contact. To locate your project manager/contact, enter your project file number on our Postcard page.
  • If you are preparing to submit an application for a permit, see information on the main permitting page or visit MyBuildingPermit.com.
  • For general information about the County’s stormwater regulations, please email Ken Crossman or call 425-262-2227.