- Atlatec, S.A. de C.V.
- Occidental Mukhaizna, LLC
- Bahamas Water and Sewerage Corporation, The Bahamas
- St. Kitts, West Indies
- University of the West Indies, Faculty of Engineering, Engineering Institute, Caribbean WaterNet
- Caribbean Water Treatment, Ltd., Codrington, Barbuda
- Sewerage and Water Board of New Orleans
- Washington Suburban Sanitary Commission (WSSC)
- District of Columbia Water and Sewer Authority (DC Water)
- City of Baltimore
- City of Columbus
- Dallas/Fort Worth International Airport
- Arch Western Bituminous Group LLC
- Borough of Avalon
- Municipal Authority of the Borough of Baden
- Bethel Park Municipal Authority
- Butler Area Sewer Authority
- Authority of the Borough of Charleroi
- Consolidated Coal Company
- Consol Energy, Inc.
- Cranberry Township
- Dominion Transmission, Inc.
- General Motors Corp.
- Municipal Authority of the Borough of Kittanning
- Koppers, Inc.
- Lima Refining Company
- Marathon Petroleum
- City of Martinsburg
- Municipal Authority of the City of Monongahela
- Monroeville Municipal Authority
- Pittsburgh Water & Sewer Authority