Integrated Regional Water Management (IRWM) is defined by the California Department of Water Resources (DWR) as a collaborative effort to manage all aspects of water resources in a region. IRWM crosses jurisdictional, watershed, and political boundaries; involves multiple agencies, stakeholders, individuals, and groups; and attempts to address the issues and differing perspectives of all the entities involved through mutually beneficial solutions.

The East Contra Costa County IRWM Region is a distinct geographic region covering 350 square miles, which is isolated from its neighboring regions by the ridge lines of Mt Diablo to the south and west, and the Delta waterways to the north and east.  The region has a long history of collaborative regional water management planning, starting with the preparation and implementation of an East County Water Management Plan in 1996, the development of a Functionally Equivalent IRWM Plan in 2005, the 2013 IRWM Plan Update and the 2015 IRWM Plan Update. The region was evaluated and formally accepted as an IRWM region by DWR in 2009.