The Washington State Department of Ecology writes and releases permits and manuals that inform and regulate stormwater management across the state. Street sweeping is a stormwater source control best management practice (BMP) already utilized by many municipalities and districts, and upcoming Phase I and Phase II MS4 permit cycles are anticipated to increase requirements surrounding street sweeping.

This project will assist in the development of a guidance manual that will provide information and tools Permittees can use to assist with developing and/or improving their street sweeping program. This effort is timed to support Permittees with meeting the anticipated 2024-2029 Municipal Separate Storm Sewer (MS4) Permit requirements, enabling these Permittees to implement a street sweeping program by July 1, 2027.