Washington State Wetland Rating Systems

The wetlands in Washington State differ widely in their functions and values. Some wetland types are common, while others are rare. Some are heavily disturbed while others are still relatively undisturbed. All, however, provide some functions and resources that are valued. These may be ecological, economic, recreational, or aesthetic. Managers, planners, and citizens need tools to understand the resource value of individual wetlands in order to protect them effectively.

The wetland rating systems were designed to differentiate between wetlands in western and eastern Washington.  They categorize wetlands into four categories based on their sensitivity to disturbance, their rarity, our ability to replace them, and the functions they provide. The rating systems, however, do not replace a full assessment of wetland functions that may be necessary to plan and monitor a project of compensatory mitigation.

The “rating” categories are intended to be used as the basis for developing standards for protecting and managing the wetlands to reduce further loss of their value as a resource. Some decisions that can be made based on the rating include the width of buffers needed to protect the wetland from adjacent development, the amount of mitigation needed to compensate for impacts to the wetland, and permitted uses in the wetland. The Department of Ecology has developed recommendations for such protective standards and these are available in volume 2 of the "Best Available Science" report.

The rating systems are primarily intended for use with vegetated, freshwater, wetlands as identified using the federal wetland delineation manual (PDF) and applicable regional supplements (Chapter 173-22-035 WAC). It also categorizes estuarine wetlands but does not characterize their functions. The rating systems do not categorize or characterize streambeds, riparian areas, and other valuable aquatic resources.

2014 Updates to the Washington State Wetland Rating Systems

Ecology has updated the Washington State Wetland Rating Systems for eastern and western Washington. These updates replace the 2004 versions of the rating systems including the annotated versions. The effective date of the 2014 rating systems is January 1, 2015.

The January 1, 2015, effective date means that if you rate a wetland on or after that date, you will be required to use the 2014 updates for projects needing Ecology authorization. An applicant applying for a local permit will need to consult with that specific local government if its critical areas ordinance (CAO) requires the use of the rating system. If a CAO contains the language “2004 rating system or as revised,” it is likely that an applicant will need to use the 2014 updates, as of January 1, 2015, to address local government requirements.

Some local jurisdictions may have language in their CAO that requires the use of the 2004 rating systems regardless of whether updates exist. The 2004 versions will, therefore, also remain available on this webpage.

> Learn more about the updates

Download the 2014 Rating Systems and Forms

Annotated Versions of the 2004 Rating Systems and Forms

The Rating System and the Credit/Debit Method

The Rating Systems should not be used to estimate the changes in the functions of wetlands as a result of impacts or mitigation. Ecology has developed a separate tool to address this issue called the Credit/Debit Method. 

> More on the Credit/Debit Method


Ecology highly recommends that users of this method take the training provided by the Department of Ecology. Ecology offered two one-day classes on the updates in June 2014. Ecology will be offering one-day and two-day classes on the 2014 Wetland Rating System Updates throughout 2015 and 2016. In order to qualify for the one-day training, you must have already taken the two-day wetland rating class for the 2004 version.  All classes will be announced through the Coastal Training Program.

Note: If you have taken the two-day training on the 2004 rating system and the one-day training on the Credit/Debit Method, Ecology will consider you to be trained in the updated rating systems. The new questions in the updates are the same as in the Credit/Debit Method.

More Information

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