Hide Alert

Welcome to our new website. Learn more about what's new.

Stormwater manuals

Our stormwater manuals provide stormwater permit implementation and management guidance. To determine which manual you need, contact your municipality or permit administrator.

Ecology's Stormwater Management Manual for Western Washington
Ecology's Stormwater Management Manual for Eastern Washington
Order a hard copy or CD

Between versions: What changed and why?

2014 Stormwater Management Manual for Western Washington (SWMMWW) revision

2012 SWMMWW revision

Other manuals for management and design

Manual equivalency

In some cases, municipal stormwater permittees have the option of either adopting portions of the appropriate Stormwater Manual or portions of a regional manual determined to be equivalent to the Ecology manual.

Other resources