Drainage & Land Disturbing Activity
Last Updated: March 2016
Updates to the County's stormwater regulations
On January 11, 2016, after a public hearing, the County Council voted to approve Ordinances Nos. 15-102 (PDF) and 15-103 (PDF) to amend the County's stormwater regulations for consistency with the Phase I Municipal Stormwater Permit ("NPDES Permit"). Under the terms of the Permit, Snohomish County's deadline for having its new regulations in effect is January 22, 2016.
For an overview of the stormwater and drainage thresholds and new requirements, review this flow chart (PDF). The flow chart provides links (coming soon) to stormwater and drainage documents needed for project application submittals.
What has changed?
Chapters 30.63A SCC (Drainage) and 30.63B (Land Disturbing Activity) have been updated as have a number of definitions in Chapter 30.91 SCC (Definitions). Chapter 30.63C SCC (Low Impact Development) has been repealed because use of low impact development (LID) best management practices (BMPs) is no longer optional under the County's NPDES Permit. The most significant change for consistency with the County's NPDES Permit is that LID BMPs are now required where feasible.
Many of the technical LID BMP requirements have been removed from Chapter 30.63A SCC and relocated in the updated Snohomish County Drainage Manual (Drainage Manual) or in the updated Engineering Design and Development Standards (EDDS).
The code changes can be reviewed in Ordinances Nos. 15-102 (PDF) and 15-103 (PDF) or in the summary notices published for each ordinance: Summary Notice Ord. No. 15-102 (PDF) and Summary Notice Ord. No. 15-103 (PDF).
New Stormwater and Drainage Requirements
The following documents comprise the new stormwater and drainage requirements.
- Chapter 30.63A SCC - Drainage
- Chapter 30.63B SCC - Land Disturbing Activity
- Chapter 7.53 SCC - Water Pollution Control
- Chapter 7.54 SCC - Maintenance of Constructed Stormwater Control Facilities
- Snohomish County Drainage Manual
- Engineering Design and Development Standards (EDDS)
What documents do you need if you want to apply for a permit or a land use action?
In addition to the permit or land use application submittal requirements (e.g., single-family home, private garage/shop, land disturbing activity, short plat, or subdivision), documentation is required for compliance with drainage requirements. Review this flow chart (PDF) to determine what thresholds are met by your proposed project and what minimum requirements (MRs) your project must address. The flow chart will provide links to documents for projects subject to:
- Minimum Requirement 2 Stormwater Pollution Prevention Plan (SWPPP) only;
- Targeted Drainage Site Plan (Minimum Requirements 1-5) and a SWPPP; and
- Construction / Full Drainage Site Plan (Minimum Requirements 1-9) and a SWPPP .
The Minimum Requirements are explained in the Drainage Manual, Volume I, Chapter 2. Guidelines for your Stormwater Site Plan (MR1) can be found in the Drainage Manual Volume I, Chapter 3. SWPPP guidance can be found in the Drainage Manual Volume I, Appendices I-F for small projects (see SCC 30.63A.810 to determine if your project qualifies as a small project), or in Volume II, Chapter 3 for Construction / Full SWPPP instructions.
- Agricultural Activities and Farm Related Business Submittal Checklist (PDF)
- Commercial Building Permit Submittal Checklist (PDF)
- Construction Full Stormwater Site Plan Checklist (PDF)
- Construction Full SWPPP Checklist and Instructions (PDF)
- Drainage Review Submittal Checklist and Form (PDF)
- LDA and Forest Practice Application Combined (PDF)
- Preliminary Short Subdivision Submittal Checklist (PDF)
- Preliminary Subdivision Submittal Checklist (PDF)
- Private Garage and Storage Structure (PDF)
- Record Drawing (As-Builts) Checklist (PDF)
- Residential Site Plan Submittal Checklist (PDF)
- Stormwater Facility Easement Submittal Checklist (PDF)
- Targeted Stormwater Site Plan Checklist (PDF)
- Utility Construction Plan Checklist (PDF)
- Utility Application Submittal Checklist (PDF)
- Notice of Intent - Construction General Permit - Indian Country (United States Environmental Protection Agency)
- Notice of Intent - Multi-Sector General Permit - Indian Country (United States Environmental Protection Agency)
- Waiver and Modification Form
- EDDS Deviation Form
- Notice of Intent - Construction Stormwater General Permit (Washington State Department of Ecology)
- Notice of Intent - Industrial Stormwater Permit (Washington State Department of Ecology)
- Land Use Pre-Application Meeting (PDF)
- Master Permit Application (PDF)
- Small Project Stormwater Pollution Prevention Plan (SWPPP) Narrative and Plan Submittal (PDF)
- Residential Application Form (PDF)
- Stormwater Facility Easement Instructions (PDF)
- Stormwater Facility Easement (PDF)
- Permitting & Information Services (PDF) - #1
- Short Subdivision (Short Plat) Approval (PDF) - #8
- Critical Area Regulations for Residential Projects (PDF) - #15
- Low Impact Development (LID) Best Management Practices (BMPs) (PDF) - #22
- Residential Garages and Storage Buildings (PDF) - #26
- Filling of Roadside Ditches (PDF) - #66
- Common Building Permit Exemptions (PDF) - #74
- Land Disturbing Activity (LDA) Terms (PDF) - #85
- Land Disturbing Activity (LDA) Permit Exemptions (PDF) - #86
- Land Disturbing Activity (LDA) Permits (PDF) - #87
- Land Disturbing Activity (LDA) Emergency Actions (PDF) - #88
- Drainage Review for Projects Vested on or after January 22, 2016 (PDF) - #89
- Stormwater Pollution Prevention for Small Projects (PDF) - #90
- Preparing a Small Project Stormwater Pollution Prevention Plan (SWPPP) (PDF) - #91
- Best Management Practices (BMPs) for Small Projects Stormwater Pollution Prevention Plans (SWPPPs) (PDF) - #92
- Post-construction Soil Standard (PDF) - #94
- Land Disturbing Activity (LDA) Plan Review and/or Inspection Fees (PDF) - #100
- Source Control Best Management Practices (BMPs) (PDF) - #101
- Reduced Drainage Requirements Allowed Under the "Exception" (PDF) - #107
- Low Impact Development Best Management Practices and Feasibility Analysis (PDF) - #108
The federal Clean Water Act (CWA) includes a permit program, the National Pollutant Discharge Elimination System (NPDES), that accounts for stormwater runoff that collects in municipal separate storm sewers (MS4s) and enters surface waters. The Environmental Protection Agency (EPA) developed rules to implement the regulations and established two phases, Phase I and Phase II, for the municipal stormwater permit program. The Washington State Department of Ecology develops and administers the NPDES municipal stormwater permits in Washington State.
The Phase I NPDES permit regulates discharges from municipal separate storm sewers owned or operated by Clark County, King County, Pierce County, and Snohomish County; and the cities of Seattle and Tacoma. The Phase II Municipal Stormwater Permit rule extends the coverage of the NPDES program to certain small municipal separate stormwater sewer systems (MS4s).
For more information, please visit the Washington Department of Ecology website.