Exhibit 21.1 Subsidiaries 1. Headwaters acquired a 100% interest in Hydrocarbon Technologies, Inc. ("HTI") by agreements entered into in May 2001 and that closed in August 2001. HTI's subsidiaries are: a. Chemsampco, Inc. ("Chemsampco"), a New Jersey corporation; b. Hydrocarbon Technologies of Canada, Inc. ("HTC"), a Canadian corporation located in the province of Alberta. 2. Headwaters is a 50% member in Environmental Technologies Group, LLC, a Utah limited liability company of which Headwaters serves as manager. ETG is a special purpose entity that owns and plans to put into operations a synthetic fuel manufacturing facility. 3. Headwaters acquired a 100% interest in Industrial Services Group, Inc. ("ISG") by agreements entered into in July 2002 and that closed in September 2002. ISG's operating subsidiary is ISG Resources, Inc., a Utah corporation. The subsidiaries of ISG Resources, Inc. are: a. ISG Canada Limited, a Canadian corporation located in the Province of New Brunswick; b. ISG Manufactured Products, Inc., a Utah corporation; c. ISG Partner, Inc., a Utah corporation; d. ISG Swift Crete, Inc., a Utah corporation; e. Flexcrete Building Systems, L.C., a Utah limited liability company; f. Best Masonry & Tool Supply, Inc., a Texas corporation; g. Don's Building Supply, L.P., a Texas limited partnership; h. Lewis W. Osborne, Inc., a California corporation; i. Magna Wall, Inc., a Texas corporation; j. Palestine Concrete Tile Company, L.P., a Texas limited partnership; k. United Terrazzo Supply Co., Inc., a California corporation. The following chart illustrates Headwaters' corporate structure. The ownership of each subsidiary is 100%, except in the case of Environmental Technologies Group, LLC, in which Headwaters owns a 50% interest: Headwaters Incorporated ----------------------- Environmental Industrial Services Technologies Hydrocarbon Group, Inc Group, LLC Technologies, Inc ---------- ---------- ----------------- ISG Resources, Inc. Chemsampco, Inc. Hydrocarbon Technologies ISG Canada Limited of Canada, Inc. ISG Manufactured Products, Inc. ISG Partner, Inc. ISG Swift Crete, Inc. Flexcrete Building Systems, L.C. Best Masonry & Tool Supply, Inc. Don's Building Supply, L.P. Lewis W. Osborne, Inc. Magna Wall, Inc. Palestine Concrete Tile Company, L.P. United Terrazzo Supply Co., Inc.