Phase I Equivalent Stormwater Manuals for Western Washington

This page provides information for Western Washington Phase I Permittees and other interested parties regarding Phase I Municipal Stormwater Permittee programs for Runoff Controls for New and Redevelopment. Ecology will post additional information on this webpage as it becomes available.

Historical information, current status, and links to the Phase I programs (including codes, ordinances, Directors’ Rules, public rules and manuals) are described below.

Programs Equivalent to the 2014 SWMMWW

All six Phase I permittees (Snohomish, King, Pierce, and Clark Counties, and the cities of Seattle and Tacoma) submitted draft codes and manuals to Ecology for review. Ecology staff evaluated the submittals for equivalency with the 2012 Stormwater Management Manual for Western Washington as Amended in December 2014 (The 2014 SWMMWW), and worked through revisions with permittees.

Preliminary Approval Documents

Ecology has not yet formally approved any programs as being equivalent to Appendix I in the Phase I Municipal Stormwater Permit (effective August 1, 2013) and the required portions (according the Municipal Stormwater Permits) of Ecology’s 2014 SWMMWW. We provided preliminary approval to the six Phase I permittees. Ecology’s determination will not become final until after we conduct a public review process associated with modification of Appendix 10 of the Phase I Permit.

Preliminary approval letters and associated documents are available at the links below.

WSDOT Highway Runoff Manual

The Department of Ecology completed its review of the 2014 Washington State Department of Transportation Highway Runoff Manual (The 2014 HRM) and found that it meets the BMP selection, design, infeasibility criteria and limitations for public road projects equivalent to Ecology's 2014 SWMMWW and 2004 Stormwater Management Manual for Eastern Washington. These are primarily located within Chapter 5 and Chapter 6 of the 2014 HRM. Other sections of the 2014 HRM contain WSDOT-specific guidance that may not be deemed part of an equivalent Program for a municipality.


Programs Equivalent to the 2005 SWMMWW

Ecology determined that the following enforceable documents, including codes, ordinances, director’s rules, public rules and/or manuals, are functionally equivalent to Appendix I in the Phase I Municipal Stormwater Permit (effective February 16, 2007) and the required portions (according the Municipal Stormwater Permits) of Ecology’s 2005 Stormwater Management Manual for Western Washington. If Ecology’s determination of equivalency is conditioned, the conditions are listed below.

King County

King County’s 2005 SWMMWW-equivalent program consists of:

City of Tacoma

Tacoma’s adopted manual and supporting documents are available at the City of Tacoma webpage.

City of Seattle

The Seattle 2005 SWMMWW equivalent program is available at the Seattle Stormwater Code webpage, and consists of:

Pierce County

Pierce County’s 2005 SWMMWW equivalent program is available at the Pierce County Stormwater Manual page, and consists of:

Snohomish County

Snohomish County’s 2005 SWMMWW equivalent program consists of:

Clark County

Clark County’s 2005 SWMMWW equivalent program consists of:

WSDOT Highway Runoff Manual

The Department of Ecology completed its review of the November 2011 Washington State Department of Transportation Highway Runoff Manual and found that it meets minimum design requirements and best management practices for public road projects equivalent to Ecology's 2005 Stormwater Management Manual for Western Washington and Eastern Washington.




Ecology contacts for Phase I and Phase II municipal stormwater permit questions

Ecology contacts for technical questions