Stormwater manuals

WA Counts 2020Respond to the 2020 Census now. An accurate count of Washington residents will ensure the fair distribution of political representation and of federal and state resources.

Help us ensure that Everyone Counts in 2020.

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


Order a hard copy or CD

Between versions: What changed and why?

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