The Storm Water Association of Maryland, Inc. (SWAM) was formed as a statewide association of local governments that own and operate regulated municipal separate storm sewer systems (MS4s). SWAM's Agency Members are:

Berlin, Town of	Frederick County
Cecil County	Howard County
Charles County	Harford County
Cumberland, City of	Washington County

In addition, leading engineering and stormwater consulting firms actively participate as affiliate members to keep abreast of changing policies and to support SWAM Agency Members with their exceptional technical expertise. The SWAM Consultant Members are:

Arcadis/Malcolm Pirnie	EA Engineering, Science & Technology
Atkins Global	Greeley and Hansen
Brown and Caldwell	Hazen and Sawyer
CDM