EXHIBIT 21.1 SOUTHWEST WATER COMPANY AND SUBSIDIARIES SUBSIDIARIES OF THE REGISTRANT (1) Jurisdiction of Name of Subsidiary Incorporation Parent ------------------ ------------- ------ Suburban Water Systems California Southwest Water Company New Mexico Utilities, Inc. New Mexico Southwest Water Company ECO Resources, Inc. Texas Southwest Water Company Water Suppliers Mobile Communication Service California Suburban Water Systems SW Resource Management Company Delaware Southwest Water Company SOCI, Inc. (2) Delaware Southwest Water Company SW Operating Services Co. (2) Delaware Southwest Water Company Southwest Environmental Laboratories, Inc. (2) Texas ECO Resources, Inc. Southern Municipal Services, Inc. (2) Texas ECO Resources, Inc. All above listed subsidiaries have been consolidated in the Registrant's financial statements. (1) As of March 17, 1995 (2) Inactive