Los Angeles, June 30, 2005 - Southwest Water Company (NASDAQ: SWWC) completed the sale of its wholly owned subsidiary, Master Tek International Inc., to Minol USA. For the past 25 years, Master Tek International has provided utility submetering and billing and collection services for multi-family residential properties nationwide. The transaction will establish Minol USA as one of the nation's top three utility allocation and submetering providers to the real estate industry, with approximately 400,000 contracted units. Duff & Phelps, LLC served as exclusive financial advisor to Southwest Water Company, initiating the transaction, leading the negotiations and rendering an opinion of fairness to the board of directors of Southwest Water.

Southwest Water Company provides a broad range of operations, management and maintenance services, including water production, treatment and distribution; wastewater collection and treatment; customer service and utility infrastructure construction management. The company owns regulated public utilities and also serves cities, utility districts and private companies under contract. More than two million people from coast to coast depend on Southwest Water for high-quality, reliable service. Additional information may be found on the company's Web site: www.swwc.com.

Minol USA (www.minolusa.com) is a Dallas based utility and financial management company, offering utility expense recovery and energy conservation solutions as well as bundled voice, video and data services to the real estate industry. Minol USA is a division of Minol International, the third largest provider of utility consumption data equipment in the world, operating in 27 countries worldwide.

Duff & Phelps is a national investment banking and financial advisory firm headquartered in Chicago, Ill., that focuses on providing merger and acquisition, private placement, valuation, financial opinion and restructuring services to middle-market companies. Since 1932, Duff & Phelps has been committed to delivering independent advice and service of exceptional quality to a broad range of public and private companies. More information on Duff & Phelps can be found at www.duffllc.com.

Contact:

Greg Range
Managing Director
(310) 712-3001