Mason County adopted a series of ordinances in June 2008 aimed at improving stormwater management. 

One significant regulatory improvement came from the adoption of the 2005 edition of Ecology’s Stormwater Management Manual for Western Washington, to be gradually applied in a phased approach and eventually used county-wide by June 2012.  (Those areas not covered by the 2005 Manual are subject to the 1992 Manual.)

A second regulatory improvement came with the adoption of the Low Impact Development
(LID) ordinance that is applicable to the Belfair and Allyn Urban Growth Areas.

Another important ordinance was adopted creating a Storm and Surface Water Utility.  This ordinance defines the utility purpose, geographic boundaries, responsibilities and organization, and financial management.

Complete ordinances can be found here:


In addition to County stormwater requirements, the Department of Ecology also requires permits for certain types of development.  You can learn more about Ecology permits here:

More about Ecology’s 2005 Stormwater Manual

More about Low Impact Development (LID):