Authorized under the Municipal Water District Act of 1911, EMWD's duties and responsibilities are further delineated in the C ... alifornia Water Code. In 1951, EMWD annexed to The Metropolitan Water District of Southern California (MWD). The population within the current 542-square-mile service area is about 687,000. EMWD's operating budget for 2009/2010 is $217 million with net assets of approximately $1.5 billion (as of June 2009). read more