| Name | State/Country |
| Abbotsford, B.C. | Canada |
| Aberdeen City Council | United Kingdom |
| Aberdeenshire Council | United Kingdom |
| Abilene | TX |
| Abu Dhabi Water & Electricity Authority | UAE |
| Acea Ato2 | Italy |
| Acquedotto Pugliese spa | Italy |
| ACTEW Corp | Australia |
| ActewAGL | Australia |
| ADAS | United Kingdom |
| Aden Governorate Water & Sanitation Corporation | Yemen |
| Admin office of Guangdong Feilaixia Water conservancy project | China |
| Affinity Water Hatfield | United Kingdom |
| Agència Catalana de l’Aigua | Spain |
| Agency for Toxic Substances and Disease Registry | GA |
| Aguas de Barrancabermeja S.A.E.S.P. | Columbia |
| Aguas do Cacado SA | Portugal |
| Aguas Provinciales de Santiago | Argentina |
| Aguas y Aguas de Pereira | Colombia |
| Aimag Pa | Italy |
| AIVE | Belgium |
| Akron Public Utilities Bureau | OH |
| Al Ain Distribution Company | UAE |
| Alameda | CA |
| Alameda County Water District | CA |
| Albemarle County Service Authority | VA |
| Albuquerque | NM |
| Alderwood Water and Wastewater District | WA |
| Alexandria | VA |
| Alhambra | CA |
| Alphen aan Rijin | Netherlands |
| Altus AFB | OK |
| Amador Water Agency | CA |
| Amber Valley Borough Council | United Kingdom |
| Anaheim | CA |
| Anchorage Water and Wastewater Utility | AK |
| Anderson Regional Water System | SC |
| Andrews Air Force Base | MD |
| Anglesey County Council | United Kingdom |
| Anglian Water | United Kingdom |
| Ann Arbor Utilities Division | MI |
| AOB2 srl | Italy |
| Aosta | Italy |
| Apa Nova | Romania |
| APELDOORN | Netherlands |
| Apple Valley Ranchos Water Company | CA |
| Aqaba | Jordan |
| Aquafin | Belgium |
| AquaMOD Ltd | Bulgaria |
| Aqwest-Bunbury Water Board | Australia |
| Arcadia | CA |
| Arcata | CA |
| Architectural Design and Research Institute of GuangDong Province | China |
| Arlington | TX |
| Arlington County | VA |
| Arup Water | Australia |
| Arvada | CO |
| Asheville | NC |
| Ashghal | Qatar |
| Ashland | OR |
| Ashley Valley Sewer Mgmt Board | UT |
| Asotin County PUD | WA |
| Aspen | CO |
| Atena Spa | Italy |
| Athens-Clarke County | GA |
| Atlanta | GA |
| Auburn | AL |
| Auckland Council | New Zealand |
| Augusta County Service Authority | VA |
| Augusta Utilities Department | GA |
| Aurora | CO |
| Austin Utilities | MN |
| Austin Water and Wastewater Utilities | TX |
| Austin, City of | TX |
| Autoridad De Acueductos Y. Alcantarillados | Puerto Rico |
| Aveco de Bondt bv | Netherlands |
| Aviano Air Force Base | Italy |
| Avion Water | OR |
| Avondale | AZ |
| AWT New Zealand | New Zealand |
| AWW | Belgium |
| Ayuntamiento de DONOSTI-San Sebastian | Spain |
| Azusa Light and Water Department | CA |
| Bakersfield | CA |
| Baldy Mesa Water District | CA |
| Ballina Shire Council | Australia |
| Baltimore | MD |
| Baltimore County Department of Public Works | MD |
| Banana Shire Council | Australia |
| Bangkok Metropolitan Authority (WDC) | Thailand |
| Banning | CA |
| Barksdale Air Force Base | LA |
| Barneveld Gemeente | Netherlands |
| Barrie, Ontario | Canada |
| Barstow | CA |
| Bartlesville | OK |
| Barwon Water | Australia |
| Bathurst Regional Council | Australia |
| Beale Air Force Base | CA |
| Beatrice | NE |
| Beijing Drainage Group | China |
| Beijing Muncipal Institute | China |
| Belgrade Waterworks and Sewerage | Serbia and Montenegro |
| Bella Vista Water District | CA |
| Bellevue | OH |
| Bellingham | WA |
| Belmont | CA |
| Beloit | WI |
| Belton | MO |
| Ben Lomond Water | Australia |
| Bend | OR |
| Benecia | CA |
| Bentonville Water Utilities | AR |
| Berkeley County Water & Sanitation | SC |
| Berliner Wasserbetriebe | Germany |
| Berryville Public Works | AR |
| Beuningen Gemeente | Netherlands |
| Beverly | MA |
| Beverly Hills | CA |
| Bhagur Municipal Council | India |
| Bhokar Municipal | India |
| Billings | MT |
| Birmingham City Council | United Kingdom |
| Birmingham Water Works Board | AL |
| Bismarck | ND |
| Black Hawk | CO |
| Blackpool Borough Council | United Kingdom |
| Bloomington | MN |
| BMWB-SBGE | Belgium |
| Bonita Springs Utilities, Inc. | FL |
| Bonners Ferry | ID |
| Borough of Poole | United Kingdom |
| Boston Water and Sewer Commission | MA |
| Bothell | WA |
| Boulder | CO |
| Bournemouth Borough Council | United Kingdom |
| Brabant Water | Netherlands |
| Bradford MDC | United Kingdom |
| Brantford, Ontario | Canada |
| Brea | CA |
| BREDA Gemeente | Netherlands |
| Brentwood | TN |
| Brevard County | FL |
| Brewster Water Department | MA |
| Brick Township Municipal Utilities Authority | NJ |
| Bristol City Council | United Kingdom |
| Bristol County Water Authority | RI |
| Bristol Water Plc | United Kingdom |
| Broad River Water Authority | NC |
| Broken Arrow | OK |
| Brookbank Consulting | United Kingdom |
| Brookfield | WI |
| Brooks Air Force Base | TX |
| Broward County | FL |
| Brunei Public Works Department | Brunei |
| Brunswick | GA |
| Brunswick & Topsham Water District | ME |
| Brush | CO |
| Bruxelles Environnement | Belgium |
| Buckhannon | WV |
| Buckley Air Force Base | CO |
| Buena Park | CA |
| Bullhead City | AZ |
| Burbank Water and Power | CA |
| Bureau of Sewerage Tokyo Metropolitan Government | Japan |
| Burlingame | CA |
| Burnaby | Canada |
| Bursa Water and Sewerage Administration | Turkey |
| Butler County | OH |
| Cabanatuan City Water District | Philippines |
| Cabarrus County Water & Sewer | NC |
| Cabot | AR |
| CADF spa | Italy |
| Cairns Water | Australia |
| Calaveras County Water District | CA |
| Caldwell | ID |
| Caledonia Water & Enviro | United Kingdom |
| Calgary Waterworks, Alberta | Canada |
| California Department of Corrections | CA |
| California Water Service Company | CA |
| Calleguas Municipal Water District | CA |
| Caloundra City Council | Australia |
| Camarillo | CA |
| Camas | WA |
| Cambridge | MA |
| Camp Pendleton – Marine Corps Base | CA |
| Camrosa Water District | CA |
| Canal De Isabel II | Spain |
| Cannock Chase DC | United Kingdom |
| Cannon Air Force Base | NM |
| Cape Canaveral Air Force Station | FL |
| Cape Coral | FL |
| Cape Girardeau | MO |
| Capistrano Valley Water District | CA |
| Capital Regional District, B.C. | Canada |
| Carlisle City Council | United Kingdom |
| Carlsbad Municipal Water District | CA |
| Carmichael Water District | CA |
| Carpinteria Valley Water District | CA |
| Carrollton | TX |
| Casa Grande | AZ |
| Casino | Australia |
| Casitas Municipal Water Disrict | CA |
| Casper | WY |
| Castaic Lake Water Agency | CA |
| Castle Pines Metropolitan District | CO |
| Castle Rock | CO |
| Castlegar, B.C. | Canada |
| Cayman Water | Cayman Islands |
| Cedar City | UT |
| Cedar Hill | TX |
| CEDD | Hong Kong |
| Center for Disease Control | GA |
| Central Arkansas Water | AR |
| Central Basin Municipal Water District | CA |
| Central Coast Water Authority | CA |
| Central Highlands Regional Council | Australia |
| Central Highlands Water Authority | Australia |
| Central Point | OR |
| Centroaguas, E.S.P. | Colombia |
| Ceres | CA |
| Cerritos | CA |
| Chandler | AZ |
| Changzhou Veolia Water | China |
| Chanhassen | MN |
| Charlotte | NC |
| Charlotte Mecklenburg Utilities | NC |
| Charnwood Borough Council | United Kingdom |
| Charter Township of Grand Blanc | MI |
| Charter Township of Meridian | MI |
| Chattanooga | TN |
| Cheltenham Borough Council | United Kingdom |
| Chengdu Longquan Water Company | China |
| ChengDu Water | China |
| Chesterfield County | VA |
| Cheyenne | WY |
| Chicago | IL |
| Chilliwack, B.C. | Canada |
| Chino | CA |
| Chino Hills | CA |
| Christchurch | New Zealand |
| Christchurch City Council | New Zealand |
| Chula Vista | CA |
| Cincinnati Metropolitan Sewer District | OH |
| Cincinnati Water Works | OH |
| Citizens Energy Group | IN |
| Citizens Utilities Company of California | CA |
| Citrus Heights Water District | CA |
| City & Borough of Juneau | AK |
| City and County of Honolulu | HI |
| City Design | New Zealand |
| City of Oconomowoc Utilities | WI |
| City West Water | Australia |
| CLABSA | Spain |
| Clackamas River Water | OR |
| Clarence City Council | Australia |
| Clark County WRD | NV |
| Clarksville | TN |
| Clarksville Water & Gas | TN |
| Clay County Utility Authority | FL |
| Clean Water Services | OR |
| Clearwater | FL |
| Clemson | SC |
| Clermont | FL |
| Clermont County | OH |
| Clermont County Water & Sewerage | OH |
| Cleveland Utilities | TN |
| Cleveland Water Division | OH |
| Clifton Water District | CO |
| Clutha District Council | New Zealand |
| Coachella Valley Water District | CA |
| Coatsville Authority | PA |
| Cocoa | FL |
| Coliban Water | Australia |
| College Station | TX |
| Colorado Springs Utilities | CO |
| Columbia County Water & Sewerage | GA |
| Columbia Water & Light | MO |
| Columbus | OH |
| Columbus AFB | MS |
| Comisión Estatal de Servicios Públicos de Tijuana (CESPT) | Mexico |
| Communaute Urbaine | France |
| Compania de Apa Buzau | Romania |
| Compton | CA |
| Concord | NC |
| Confederación Hidrográfica del Tajo | Spain |
| Connecticut Water Company | CT |
| Consell Comarcal | Spain |
| Consolidated Mutual Water Company | CO |
| Consolidated Utility District of Rutherford County | TN |
| Consorzio di Bonifica Cellina Meduna | Italy |
| Consorzio di Bonifica dell´Emilia Centrale | Italy |
| Consorzio di Bonifica della Romagna | Italy |
| Contra Costa Water District | CA |
| Conway Corporation | AR |
| Conwy County Council | United Kingdom |
| Coquitlam, B.C. | Canada |
| Coralville | IA |
| Corner Brook | Canada |
| Cornwall County Council | United Kingdom |
| Cornwall, Ontario | Canada |
| Corona | CA |
| Corpus Christi | TX |
| Corvallis | OR |
| Council of Development and Reconstruction Water Authority of Beirut | Lebanon |
| Council of Development and Reconstruction Water Authority of Bekaa | Lebanon |
| Council of Development and Reconstruction Water Authority of Mount Lebanon | Lebanon |
| County of Henrico | VA |
| County of Pierce | WA |
| County of Sacramento | CA |
| County of Santa Cruz | CA |
| County Sanitation Districts of Los Angeles County | CA |
| Covington | GA |
| Covington Water District | WA |
| Cowlitz County PUD | WA |
| Cradle Mountain Water | Australia |
| Crescenta Valley Water District | CA |
| Crossville | TN |
| CSJ Water Pollution Control - San Jose | CA |
| Cucamonga County Water District | CA |
| Dahlonega | GA |
| Dallas | OR |
| Dallas Water Utilities | TX |
| Dalton Utilities | GA |
| Dammam | Saudi Arabia |
| Damyang Country Office | Korea |
| Dandridge Water Management Facility | TN |
| Danville | VA |
| Davis | CA |
| Davis Monthan Air Force Base | AZ |
| Dayton Water Department | OH |
| Daytona Beach | FL |
| Decatur Utilities | AL |
| Deerfield Beach | FL |
| DeKalb County Government | GA |
| Delray Beach | FL |
| Delta | CO |
| Den Haag | Netherlands |
| Denton | TX |
| Denver Water | CO |
| Department of Environmental Services, Cuyahoga Falls | OH |
| Dept. of Agriculture and Rural Development | United Kingdom |
| Dept. of Water Supply | HI |
| Derby City Council | United Kingdom |
| Derbyshire County Council | United Kingdom |
| Desert Water Agency | CA |
| Development Authority of the North Country | NY |
| Devon County Council | United Kingdom |
| Dhara Consultants Co., Ltd. | Thailand |
| DHV BV | Netherlands |
| Dirección de Adaptación al Cambio Climático y Gestión Estratégica del Riesgo, MOP-DACGER | El Salvador |
| District Municipality of Muskoka | Canada |
| District of Mission, B.C. | Canada |
| District of North Vancouver | Canada |
| District of Saanich | Canada |
| Dodge City, City of | KS |
| DOE NI Water Services | United Kingdom |
| Dolomiti Energia spa | Italy |
| Donegal County Council | Ireland |
| Dott Dario Guagnini | Italy |
| Douglasville-Douglas County Water | GA |
| Dover | DE |
| Dover | NH |
| Downey | CA |
| Doyon Utilities | AK |
| Dracut Water Supply District | MA |
| Drainage Services Department | Hong Kong |
| Draper | UT |
| Drechsteden Ingenieursbureau | Netherlands |
| Dubai Electricity and Water Authority (DEWA) | UAE |
| Dubai Municipality | UAE |
| Dubbo City Council | Australia |
| Dublin City Council | Ireland |
| Dublin San Ramon Services District | CA |
| Dun Laoghaire Rathdown | Ireland |
| Dundalk UDC | Ireland |
| Dundee City Council | United Kingdom |
| Dunedin City Council | New Zealand |
| DuPage Water Commission | IL |
| Durango | CO |
| Dyess Air Force Base | TX |
| East Bay Dischargers Authority | CA |
| East Bay Municipal Utility District | CA |
| East Larimer County Water District | CO |
| East Orange Water Commission | NJ |
| East Providence | RI |
| East Riding District Council | United Kingdom |
| East Riding of Yorkshire Council | United Kingdom |
| East Valley Water District | CA |
| Eastern Band of Cherokee Indians | NC |
| Eastern Municipal Water District - Perris | CA |
| Easton Utilities | MD |
| Ecole Polytechnique de Montreal, Quebec | Canada |
| Edmonds | WA |
| Effingham County | GA |
| EGIS EAU | France |
| El Dorado Irrigation District | CA |
| El Paso | TX |
| El Toro Water District | CA |
| Elgin | IL |
| Elk Grove Water District | CA |
| Ellesmere Port & Neston BC | United Kingdom |
| Ellington Air National Guard Base - Houston | TX |
| Ellsworth Air Force Base | SD |
| Eloy | AZ |
| Elsinore Valley Municipal Water District | CA |
| EMASA | Spain |
| Empresa de Acueductos y Alcantarillado de Pereira S.A E.S.P | Colombia |
| Empresa de Acueductos y Alcantarillado de Villavicencio E.S.P. | Colombia |
| Empresas Municipales de Cali EICE ESP (EMCALI) | Colombia |
| Englewood | CO |
| Englewood Water District | FL |
| Environment Agency | United Kingdom |
| EPAMA | France |
| EPCOR USA | AZ |
| EPD - SIG | Hong Kong |
| Erie Water Works | PA |
| ESBI Engineering & FM Ltd. | Ireland |
| Escondido | CA |
| eThekwini Municipality | South Africa |
| Eugene Water & Electric Board | OR |
| Eurobodalla Shire Council | Australia |
| Evanston | IL |
| Everett | WA |
| Evesham Municipal Utilities Authority | NJ |
| Exeter City Council | United Kingdom |
| Fair Oaks Water District | CA |
| Fairfax | VA |
| Fairfax County Wastewater Management | VA |
| Fairfax Water | VA |
| Falls Church | VA |
| Far North District Council | New Zealand |
| Fargo | ND |
| Fayetteville | AR |
| Fayetteville | NC |
| Federal Electricity and Water Authority | UAE |
| Federal Law Enforcement Training Center | GA |
| Fingal County Council | Ireland |
| First Utility District of Knox County | TN |
| Florida Keys Aqueduct Authority | FL |
| Folsom | CA |
| Fontana | CA |
| Forest of Dean DC | United Kingdom |
| Forsyth County Department of Water & Sewer | GA |
| Fort Collins - Loveland Water District | CO |
| Fort Collins Water Utilities | CO |
| Fort Lauderdale | FL |
| Fort Meyers | FL |
| Fort Pierce Utilities Authority | FL |
| Fort Walton Beach | FL |
| Fort Worth | TX |
| Fort Worth Water Department | TX |
| Foster City | CA |
| Fountain | CO |
| Fountain Sanitation District | CO |
| Fountain Valley | CA |
| Franklin District Council | New Zealand |
| Frederick | MD |
| Fresno | CA |
| Frisco | TX |
| Fullerton | CA |
| Fulton County | GA |
| Gainesville | GA |
| Gallup | NM |
| Galt | CA |
| Garden City | ID |
| Garden Grove | CA |
| Gardena | CA |
| GEI Spa | Italy |
| Gemeente Arnhem | Netherlands |
| Gemeente Borsele | Netherlands |
| Gemeente Smallingerland | Netherlands |
| Gemeente Tholen | Netherlands |
| Gemeente Utrecht | Netherlands |
| General Directorate for Water and Sewerage | Kurdistan |
| Genesee County | MI |
| Georgetown Municipal Water & Sewer Service | KY |
| Georgetown, City of | TX |
| Gila River Indian Community | AZ |
| GIMS | South Africa |
| Gladstsone City Council | Australia |
| Glasgow City Council | United Kingdom |
| Glen Ellyn | IL |
| Glendale | CA |
| Glendale Water Department | CA |
| Glendora | CA |
| Glenorchy City Council | Australia |
| Global Water Resources | AZ |
| Gloucestershire County Council | United Kingdom |
| Gold Coast Water | Australia |
| Golden State Water Company | CA |
| Goleta Water District | CA |
| Goleta West Sanitary District | CA |
| Golsboro | NC |
| Goodfellow AFB | TX |
| Goodyear | AZ |
| Gosford City Council | Australia |
| Goulburn Valley Water | Australia |
| Grampians Region Water Authority | Australia |
| Grand Forks | ND |
| Grand Island | NE |
| Grand Nancy | France |
| Grand Prairie | TX |
| Grand Rapids | MI |
| Grand Water & Sewer Service Agency | UT |
| Grants Pass | OR |
| Grapevine | TX |
| Greater Augusta Utility | ME |
| Greater Wellington Regional Council | New Zealand |
| Greeley | CO |
| Green Bay Water Utility | WI |
| Greensboro | NC |
| Greenville | SC |
| Greenville Utilities Comission | NC |
| Greenwood CPW | SC |
| Greer Commission of Public Works | SC |
| Gresham | OR |
| Grinnell | IA |
| Groveland Community Services District | CA |
| Guam Environmental Protection Agency | Guam |
| Guam Naval Facilities | Guam |
| Guam Waterworks Authority | Guam |
| Guangzhou PSDRI | China |
| Guelph, Ontario | Canada |
| Gulf Coast Water Authority | TX |
| Gumi Waterworks and Sewerage Affairs | Korea |
| Gunnedah Shire Council | Australia |
| Haarlem | Netherlands |
| Hagerstown | MD |
| Halcrow Group, Ltd. | United Kingdom |
| Hallsdale-Powell Utility District | TN |
| Hamilton Township Municipal Utilities Authority | NJ |
| Hampton Roads Sanitation District | VA |
| Hannibal Board of Public Works | MO |
| Hanover County | VA |
| Harborough District Council | United Kingdom |
| Harpeth Valley Utilities District | TN |
| Harriman Utility Board | TN |
| Harrison | AR |
| Hastings District Council | New Zealand |
| Haverhill | MA |
| Hawthorne | CA |
| Hayward | CA |
| HEERLEN Gemeente | Netherlands |
| Helena | MT |
| Helix Water District | CA |
| Hemet | CA |
| Henderson | NV |
| Henderson Water Utility | KY |
| Hendersonville | NC |
| Hera Bologna s.r.l. | Italy |
| Hera Spa | Italy |
| Hermiston | OR |
| Hertsmere Borough Council | United Kingdom |
| Hesperia | CA |
| Hidrolara C.A. | Venezuela |
| Higginsville | MO |
| Highline Water District | WA |
| Hill Air Force Base | UT |
| Hillsborough | CA |
| Hillsborough County | FL |
| Hilton Head Public Service District | SC |
| Hilvarenbeek | Netherlands |
| Hobart Water | Australia |
| Hodeidah Water and Sanitation Local Corporation (HWSLC) | Yemen |
| Holbrook | MA |
| Holland Board of Public Works | MI |
| Hollister | CA |
| Holloman Air Force Base | NM |
| Hollywood | FL |
| Homer | AK |
| Hong Kong Airport Authority | Hong Kong |
| Hong Kong Water Supplies Department | Hong Kong |
| Honolulu Board of Water Supply | HI |
| Hood River | OR |
| Hot Springs | AR |
| Houston | TX |
| Howard County | MD |
| HQ Pacific Air Forces | HI |
| HRSD | VA |
| Hunter Water | Australia |
| Hurunui District Council | New Zealand |
| Iberville | LA |
| IBGE - BIM | Belgium |
| Idaho Falls | ID |
| IDEA | Belgium |
| IGRETEC | Belgium |
| INASEP | Belgium |
| Independence | MO |
| Indian Health Service | AL |
| Indian Health Services | NM |
| Indian Wells Valley Water District | CA |
| Indianapolis Water Company | IN |
| Indio | CA |
| Infrax cvba | Belgium |
| Inglewood | CA |
| Inland Empire Utilities Agency | CA |
| IPALLE, Intercommunale | Belgium |
| Ipswich Borough Council | United Kingdom |
| Ipswich City Council | Australia |
| Iren Spa | Italy |
| Irvine Ranch Water District | CA |
| Irving | TX |
| Issaquah | WA |
| Ithaca | NY |
| Jackson Energy Authority | TN |
| Jacksonville | NC |
| JEA | FL |
| Jeddah | Saudi Arabia |
| Jefferson Parish Department of Water | LA |
| JKR (Dept of Public Works) | Malaysia |
| Johnson County Special Utility District | TX |
| Johnson County Wastewater | KS |
| Joplin | MO |
| Jordan Valley Authority | Jordan |
| Joshua Basin Water District | CA |
| JPS HQ | Malaysia |
| Kadena Air Force Base | Japan |
| Kahramaa, Water Networks Affairs | Qatar |
| Kalamazoo | MI |
| Kansas City | MO |
| Kapiti Coast District Council | New Zealand |
| Kaysville | UT |
| Kearns Improvement District | UT |
| Keene | NH |
| Keesler AFB | MS |
| Kelowna City, B.C. | Canada |
| Kennedy Space Center | FL |
| Kenner | LA |
| Kerrville | TX |
| Kildare County Council | Ireland |
| Killeen | TX |
| Kingston, Ontario | Canada |
| Kitchener, Ontario | Canada |
| Klamath Falls | OR |
| Knoxville Utilities Board | TN |
| Kopargaon Municipal Council | India |
| Kunming | China |
| Kurdistan Regional Government | Iraq |
| La Crosse | WI |
| La Habra | CA |
| La Louviere | Belgium |
| La Palma | CA |
| Lacey Public Works | WA |
| Lafayette Utilities System | LA |
| LaFollette Utilities | TN |
| Laguna Beach County Water District | CA |
| Laguna Madre Water District | TX |
| Lajes Air Force Base | Portugal |
| Lake Arrowhead | CA |
| Lake County | IL |
| Lake Havasu | AZ |
| Lake Oswego | OR |
| Lake Whatcom Water and Sewer District | WA |
| Lake Worth | FL |
| Lakeway Municipal Utility District | TX |
| Lakewood | CA |
| Langley Air Force Base | VA |
| Langley, B.C. | Canada |
| Lansing Board of Water & Light | MI |
| Laois County Council | Ireland |
| Largo | FL |
| Las Cruces | NM |
| Las Vegas | NV |
| Las Vegas Valley Water District | NV |
| Las Virgenes Municipal Water District | CA |
| Latham Water District | NY |
| Laughlin Air Force Base | TX |
| Launceston City Council | Australia |
| Laurens County Water & Sewer Comm. | SC |
| LaVerne | CA |
| Lawrenceville | GA |
| Lawton | OK |
| LDS Church | UT |
| Le Grand Chalon | France |
| League City | TX |
| Lee County Regional Water Supply Authority | FL |
| Lee County Utilities | FL |
| Leeds City Council | United Kingdom |
| Lee's Summit | MO |
| Lehigh County Authority | PA |
| Leicester City Council | United Kingdom |
| Lembaga Air Perak | Malaysia |
| Letong, Ltd. | China |
| Lewiston | ID |
| Lewiston | ME |
| Liberty Chesnee Fingerville Water District | SC |
| Limerick Corporation | Ireland |
| Limestone County Water and Sewer | AL |
| Lincoln | AR |
| Lincoln | CA |
| Lincoln Wastewater System | NE |
| Lincoln Water System | NE |
| Lismore City Council | Australia |
| Little Rock Wastewater Utility | AR |
| Liuzhou Water company | China |
| Livermore | CA |
| Liverpool City Engineers | United Kingdom |
| Logan | UT |
| Logan City Council | Australia |
| Lompoc | CA |
| London Borough of Enfield | United Kingdom |
| London Borough of Havering | United Kingdom |
| London, City of | Canada |
| London, Ontario | Canada |
| Longmont | CO |
| Longview | WA |
| Los Alamos | NM |
| Los Angeles Department of Public Works | CA |
| Los Angeles Department of Water and Power | CA |
| Los Angeles DWP Recycled Dept | CA |
| Los Osos Community Services District | CA |
| Lotti | Italy |
| Louisiana Utilities, Inc. | LA |
| Louisville & Jefferson County MSD | KY |
| Louisville Water Company | KY |
| Loveland | OH |
| Loveland Water and Power | CO |
| Lower Murray Water | Australia |
| Lubbock | TX |
| Lumpkin County Water and Sewerage Authority | GA |
| Lynchburg | VA |
| Lynwood | WA |
| Madison Water Utility | WI |
| Magalies Water | South Africa |
| Mammoth Community Water District | CA |
| Manassas | VA |
| Manawatu District Council | New Zealand |
| Manchester Water Works | NH |
| Manitowoc Public Utilities | WI |
| Mansfield | TX |
| Mansfield District Council | United Kingdom |
| Manteca | CA |
| Manukau Water | New Zealand |
| Marafiq | Saudi Arabia |
| Marco Island | FL |
| Margate | FL |
| Marietta | GA |
| Marin Municipal Water District | CA |
| Marina Coast Water District | CA |
| Marine Corps Air Station - Cherry Point | NC |
| Marion County Utilities | FL |
| Markham | Canada |
| Marlborough District Council | New Zealand |
| Marquette | MI |
| Marysville | WA |
| Massachusetts Water Resources Authority | MA |
| Matamata-Piako District Council | New Zealand |
| Matsuyama City | Japan |
| Maxwell AFB | GA |
| Mayo County Council | Ireland |
| McAllen | TX |
| McEntire Air National Guard Station - Eastover | SC |
| McGuire Air Force Base | NJ |
| McKinney | TX |
| Medford | MA |
| Medford Water Commission | OR |
| Melbourne Water | Australia |
| Memphis | TN |
| Memphis Light, Gas & Water Dept. | TN |
| Menlo Park | CA |
| Meridian | ID |
| Mesa | AZ |
| Mesa Consolidated Water District | CA |
| Metro Wastewater | CO |
| Metropolitan Borough of Wirral | United Kingdom |
| Metropolitan District of Connecticut | CT |
| Metropolitan Utilities District | NE |
| Metrowater | New Zealand |
| Miami Dade Water and Sewer Department | FL |
| Michigan City | IN |
| Midland | TX |
| Midvalley Improvement District | UT |
| Millbrae Public Works | CA |
| Milpitas | CA |
| Milwaukee | WI |
| Milwaukie | OR |
| Ministere de la Region de Bruxelles-Capitale | Belgium |
| Ministère Wallon de L'équipement & Transport de la Regionne Wall | Belgium |
| Ministry of Electricity & Water | Kuwait |
| Ministry of Electricity and Water | Bahrain |
| Ministry of Municipalities & Public Works | Iraq |
| Ministry of Municipality & Urban Planning | Qatar |
| Ministry of Water and Irrigation | Jordan |
| Ministry of Works and Energy | Fiji |
| Minneapolis | MN |
| Minot Air Force Base | ND |
| Mission Springs Water District | CA |
| Mobile County Water, Sewer & Fire Protection Authority | AL |
| Modesto | CA |
| Mohawk Valley Water Authority | NY |
| Moline | IL |
| Monroe | NC |
| Monroe | WA |
| Monroe County Water Authority | NY |
| Monroe Township Municipal Utilities Authority | NJ |
| Montara | CA |
| Monte Vista Water District | CA |
| Montecito Water District | CA |
| Montezuma Water Company | CO |
| Montgomery County | OH |
| Montgomery Water and Sewer Board | AL |
| Montrose | CO |
| Moore County | NC |
| Moorhead Public Service | MN |
| Moreton Bay Water | Australia |
| Morgan Hill | CA |
| Morrison Utility Services | Arlesey |
| Moulton Niguel Water District | CA |
| Mount Laurel Township | NJ |
| Mount Pleasant | MI |
| Mount Pleasant Waterworks | SC |
| Mountain View | CA |
| Mountain Water Company | MT |
| Mt. Crested Butte Water & Sanitation District | CO |
| Mt. Home Air Force Base | ID |
| Muko City | Japan |
| Munakata City | Japan |
| Murfreesboro | TN |
| Muscatine Power & Water | IA |
| Muskegon | MI |
| Muskogee | OK |
| Nacogdoches | TX |
| Nadi-Lautoka Regional Water Supply | Fiji |
| Napa County Resource Conservation District | CA |
| Napa Department of Public Works | CA |
| Nashville Metropolitan Water Services | TN |
| National Naval Medical Center | MD |
| National Water Commission | Jamaica |
| National Water Company – Jeddah City | Saudi Arabia |
| National Water Company – Riyadh City | Saudi Arabia |
| National Weather Service | TX |
| Navajo Environmental Protection Agency | AZ |
| Navajo Tribal Utility Authority | AZ |
| Naval Surface Warfare Center - Carderock | MD |
| Navy Public Works Center - Illinois | IL |
| Navy Public Works Center - Washington Navy Yard | Washington D.C. |
| Nellis Air Force Base | NV |
| Nelson City Council | New Zealand |
| Nevada Irrigation District | CA |
| New Braunfels Utilitie | TX |
| New Forest District Council | United Kingdom |
| New Kent County | VA |
| New London | CT |
| New Orleans, City of | LA |
| New Plymouth District Council | New Zealand |
| New Westminster | Canada |
| New York City DEP | NY |
| New York City Department of Environmental Protection | NY |
| Newark | NJ |
| Newberg | OR |
| Newberry | SC |
| Newhall County Water District | CA |
| Newnan Utilities | GA |
| Newport | RI |
| Newport Beach | CA |
| Newport News | VA |
| Newport Utilities | TN |
| Newton | MA |
| Newton County Water and Sewer | GA |
| Niagara Falls, Ontario | Canada |
| Noreade | France |
| Norman | OK |
| North East Lincolnshire Council | United Kingdom |
| North Huntingdon Township Municipal Authority | PA |
| North Las Vegas | NV |
| North Lincolnshire Council | United Kingdom |
| North Miami Beach | FL |
| North Penn Water Authority | PA |
| North Richland Hills | TX |
| North Shore City Council | New Zealand |
| North Tahoe Public Utility District | CA |
| North Texas Municipal Water District | TX |
| North Vancouver, B.C. | Canada |
| North Weld County Water District | CO |
| North West Leicestershire DC | United Kingdom |
| Northeast Ohio Regional Sewer District | OH |
| Northern Kentucky Water District | KY |
| Northern Territory Power and Water Authority (NTPAWA) - Darwin | Australia |
| Northglenn | CO |
| Northland Regional Council | New Zealand |
| Northshore Utility District | WA |
| Northstar Community Services District | CA |
| Northumbrian Water | United Kingdom |
| Norwalk First Taxing District Water Dept. | CT |
| Norwich City Council | United Kingdom |
| Novi | MI |
| NSW Public Works | Australia |
| Nuneaton & Bedworth BC | United Kingdom |
| Oak Harbor | WA |
| Oak Lodge Water District | OR |
| Oakland Park | FL |
| Oasen | Netherlands |
| Oberlin | OH |
| Oceanside | CA |
| O'Fallon | MO |
| Offut Air Force Base | NE |
| Ogden | UT |
| Ohio Regional Sewer District | OH |
| Oklahoma City | OK |
| Olathe | KS |
| Old Dominion Utility Services | VA |
| Old North Utility Services Inc. | NC |
| Omaha | NE |
| Onieda County Health Department | NY |
| Onondaga County Water Authority | NY |
| Ontario | CA |
| Ontario Municipal Utilities Company | CA |
| OPZOEKINGSCENTRUM WEGENBOUW | Belgium |
| Orange | CA |
| Orange County Sanitation District | CA |
| Orange County Utilities | FL |
| Orange County Water District | CA |
| Orangeburg | SC |
| Orangevale | CA |
| Oregon City | OR |
| Orem | UT |
| Orlando Utilities Commission | FL |
| Ormond Beach | FL |
| Otay Water District | CA |
| Ottawa | Canada |
| Oviedo | FL |
| Owasso | OK |
| Owensboro Municipal Utilities | KY |
| Padre Dam Municipal Water District | CA |
| Palm Beach County Water Utilities | FL |
| Palm Coast | FL |
| Palmdale Water District | CA |
| Palmerston North City Council | New Zealand |
| Palmetto State Utility Services | SC |
| Palo Alto | CA |
| Palos Heights Public Works | IL |
| Panama City | FL |
| Paragould Light Water & Cable | AR |
| Paramount | CA |
| Park City | UT |
| Park Water Company | CA |
| Pasadena Water & Power | CA |
| Pasco County Utilities | FL |
| Passaic Valley Sewerage Commission | NJ |
| Patrick Air Force Base | FL |
| PCWF - Program Alliance | Australia |
| Pearland | TX |
| Pembrokeshire County Council | United Kingdom |
| Perak Water Board | Malaysia |
| Petaluma | CA |
| Peterborough City Council | United Kingdom |
| Philadelphia Water Department | PA |
| Phoenix | AZ |
| Phoenix | OR |
| Pickering | OH |
| Pico Water District | CA |
| PIDPA | Belgium |
| Pima CountyInformation Technology Dept. | AZ |
| Pine Rivers Shire Council | Australia |
| Pitt Meadows | Canada |
| Pittsburg | CA |
| Pittsburgh Water & Sewer | PA |
| Placer County Water Agency | CA |
| Planeación Sistemasy Control | Mexico |
| Pleasanton | CA |
| Plymouth City Engineers | United Kingdom |
| Pocatello | ID |
| Pomona | CA |
| Pompano Beach | FL |
| Port Colborne, Ontario | Canada |
| Port of Oakland | CA |
| Porterville | CA |
| Portland | TN |
| Portland Water District | ME |
| Portsmouth | NH |
| Poulsbo | WA |
| Poway | CA |
| Prescott | AZ |
| Preston Borough Council | United Kingdom |
| Prince George, B.C. | Canada |
| Prince William County Service Authority | VA |
| Prineville | OR |
| Procalcula Prosis S.A. | Columbia |
| Providence Water Supply Board | RI |
| Province de Antwerpen | Belgium |
| Province de Luxembourg | Belgium |
| Province Du Hainaut | Belgium |
| Province Vlaams Brabant | Belgium |
| Provincia Regionale di Ragusa | Italy |
| Provinciebestuur LIMBURG, 3e Directie | Belgium |
| Provo City Department of Water | UT |
| Public Health Engineering | India |
| Public Utility Company of Harnett County | NC |
| Public Water Supply District No. 2 of Cass | MO |
| Pudong Veolia | China |
| Pueblo Board of Water Works | CO |
| Puerto Rico Aqueducts & Sewer Authority | Puerto Rico |
| Pullman | WA |
| Punta Gorda | FL |
| Purmerend Gemeente | Netherlands |
| Qatar General Electricity & Water Corporation (KAHRAMAA) | Qatar |
| Queensland Urban Utilities | Australia |
| Queensland Water Commission | Australia |
| Radford | VA |
| Rainbow Municipal Water District | CA |
| Raleigh | NC |
| Ramona Municipal Water District | CA |
| Rancho California Water District | CA |
| Randolph Air Force Base | TX |
| Rapid City | SD |
| Raymore | MO |
| Red Bluff | CA |
| Redcliffe City Council | Australia |
| Redding | CA |
| Redmond | OR |
| Regional Municipality of Durham, Ontario | Canada |
| Regional Municipality of Halton, Ontario | Canada |
| Regional Municipality of Niagara, Ontario | Canada |
| Regional Municipality of Peel, Ontario | Canada |
| Regional Municipality of Waterloo, Ontario | Canada |
| Regional Municipality of York, Ontario | Canada |
| Regione Piemonte | Italy |
| Renfrewshire Council | United Kingdom |
| Renton | WA |
| Rialto | CA |
| Richardson | TX |
| Richmond | CA |
| Richmond | VA |
| Richmond, B.C. | Canada |
| Rincon del Diablo MWD | CA |
| Rio Rancho | NM |
| Riobra | Belgium |
| Ripon | CA |
| Rivanna Water & Sewer Authority | VA |
| Riverina Water County Council | Australia |
| Rivers Agency Northern Ireland | United Kingdom |
| Riverside | CA |
| Riviera Beach | FL |
| Riyadh | Saudi Arabia |
| Roamingwood Sewer and Water Association | PA |
| Robertsdale | AL |
| Robins Air Force Base | GA |
| Rochdale MBC | United Kingdom |
| Rochester | NY |
| Rock Hill | SC |
| Rock Island | IL |
| Rockdale County Water Resources | GA |
| Rockford | IL |
| Rockville | MD |
| Rockwood P.U.D. | OR |
| Rogers Water Utilities | AR |
| Rogue Valley Sewer Services | OR |
| Rome Water District | NY |
| Roseville | CA |
| Ross County Water Company | OH |
| Ross Valley Sanitation District | CA |
| Roswell | GA |
| Rotherham Borough Council | United Kingdom |
| Rotorua District Council | New Zealand |
| Rous County Council at Lismore | Australia |
| Royal Commission for Jubail and Yanbu | Saudi Arabia |
| Rubidoux Community Services District | CA |
| Rushcliffe Borough Council | United Kingdom |
| RWE Thames Water | United Kingdom |
| S C Compania de Apa Arie S A Turda | Romania |
| S.C. Apa Canal S.A. | Romania |
| S.C. RAJA S.A. Constanta | Romania |
| S.P.G.E. | Belgium |
| SA Water | Australia |
| SABESP | Brazil |
| Sachse | TX |
| Sacramento County | CA |
| Sacramento Regional CSD | CA |
| Sacramento Suburban Water District | CA |
| Saigon Water Corporation | Vietnam |
| Salem City | UT |
| Salinas | CA |
| Salisbury | MD |
| Salisbury - Rowan Utilities | NC |
| Salt Lake City | UT |
| Salt River Pima Maricopa Indian Community | AZ |
| Sammamish Plateau Water & Sewer | WA |
| Samoa Water Authority | Samoa |
| San Angelo | TX |
| San Antonio River Authority | TX |
| San Antonio Water System | TX |
| San Benito County Water District | CA |
| San Bernardino | CA |
| San Diego Data Processing Corp | CA |
| San Dieguito Water District | CA |
| San Elijo Joint Powers Authority | CA |
| San Fernando | CA |
| San Francisco Department of Public Works | CA |
| San Francisco International Airport | CA |
| San Jose | CA |
| San Jose Municipal Water System | CA |
| San Juan Capistrano | CA |
| San Juan Water District | CA |
| Sanaa Water and Sanitation Local Corporation | Yemen |
| Sand Springs | OK |
| Sandia Peak Utility | NM |
| Sandwell MBC | United Kingdom |
| Sandy City Public Utilities | UT |
| SANEPAR | Brazil |
| Sanford Water District | ME |
| Sanitation District No 1 | KY |
| San-Mateo | CA |
| Santa Ana Watershed Project Authority | CA |
| Santa Barbara | CA |
| Santa Clara | CA |
| Santa Clara Valley Water District | CA |
| Santa Clarita Water Company | CA |
| Santa Cruz | CA |
| Santa Fe | NM |
| Santa Fe Irrigation District | CA |
| Santa Maria | CA |
| Santa Monica | CA |
| Santa Rosa | CA |
| Saskatoon, Saskatchewan | Canada |
| Savannah | GA |
| Scottish Water | United Kingdom |
| Scottsdale | AZ |
| Scranton Sewer Authority | PA |
| Seattle Public Utilities | WA |
| Sefton MBC | United Kingdom |
| Sellafield | United Kingdom |
| Selma-Kingsburg-Fowler County Sanitation District | CA |
| Sembcorp Bournemouth Water | United Kingdom |
| Seminole County Government - Environmental Services Department | FL |
| Sendai City | Japan |
| Sepa | United Kingdom |
| Service Public de Wallonie | Belgium |
| Seureca Muscat, LLC | Oman |
| Severn Trent Water | United Kingdom |
| Sewerage & Water Board of New Orleans | LA |
| Seymour-Johnson Air Force Base | NC |
| Shafter | CA |
| Shanghai Drainage Institute | China |
| Shanghai Municipal Engineering Design Institute | China |
| Shanghai Municipal Water Supply Dispatching and Monitoring Center | China |
| Shanghai Water Planning & Design Research Inst | China |
| Shaw Air Force Base | SC |
| Shawnee | OK |
| Shelby | NC |
| Shelton | WA |
| Shenzhen Water (Group) Co Limited | China |
| Sheppard AFB | TX |
| Shepway Engineering Services | United Kingdom |
| Sherwood | AR |
| Shorelands Water Co., Inc. | NJ |
| Show Low | AZ |
| Shreveport | LA |
| Sierra Vista | AZ |
| Siloam Springs | AR |
| Simi Valley | CA |
| SIMTEJO | Spain |
| Singapore Public Utilities Board (PUB) | Singapore |
| Sioux Falls | SD |
| SJWD Water District | SC |
| Skagit County PUD | WA |
| Slidell | LA |
| Sligo County Council | Ireland |
| Snohomish County PUD | WA |
| Social Fund for Development | Yemen |
| Sofiyska Voda | Bulgaria |
| SOGESID | Italy |
| Somerton | AZ |
| Somerville | MA |
| Sonoma County Water Authority | CA |
| Soquel Creek Water District | CA |
| South Adams County Water & Sanitation | CO |
| South Australian Water Corporation | Australia |
| South Coast Water District | CA |
| South Dublin County Council | Ireland |
| South East Water | United Kingdom |
| South East Water Limited | Australia |
| South Fort Collins Sanitation District | CO |
| South Jordan | UT |
| South Mesa Water Company | CA |
| South Placer MUD | CA |
| South Somerset District Council | United Kingdom |
| South Staffordshire Water PLC | United Kingdom |
| South Tahoe PUD | CA |
| South Taranaki District Council | New Zealand |
| South West Water | Australia |
| South West Water Plc | United Kingdom |
| Southampton City Council | United Kingdom |
| Southern Downs Regional Council | Australia |
| Southern Nevada Water Authority | NV |
| Southern Water | Australia |
| Southern Water | United Kingdom |
| Southgate Water & Sanitation Districts | CO |
| Southington Water Department | CT |
| Southwest Regional Water District | OH |
| SouthWest Water Company | TX |
| Spartanburg Sanitary Sewer District | SC |
| Spartanburg Water System | SC |
| Special Districts of San Bernardino County | CA |
| Spencer Municipal Utlities | IA |
| SPGE | Belgium |
| Spokane | WA |
| Spokane County Public Utility | WA |
| Spotsylvania County Utilities | VA |
| Springdale | AR |
| Springfield Office Public Utilities | IL |
| Springfield Water and Sewer Commission | MA |
| Springville | UT |
| St Petersburg | FL |
| St. Bernard Parish Government | LA |
| St. Catharines, Ontario | Canada |
| St. Charles County Public Water Supply Dist #2 | MO |
| St. George | UT |
| St. Helena | CA |
| St. Johns County | FL |
| St. John's, Newfoundland | Canada |
| St. Paul Water Utility | MN |
| St. Vrain Sanitation District | CO |
| Stad Antwerpen | Belgium |
| Stafford County Utilities Department | VA |
| Staffordshire County Council | United Kingdom |
| Staffordshire Moorlands DC | United Kingdom |
| Stark County Metropolitan Sewer District | OH |
| Startex-Jackson-Wellford-Duncan Water District (SJWD) | SC |
| States of Guernsey | United Kingdom |
| States of Jersey | United Kingdom |
| Statesville | NC |
| Steamboat Springs | CO |
| Stillwater | OK |
| Stockton | CA |
| Stoke-on-Trent City Council | United Kingdom |
| Submarine Base Kings Bay | GA |
| Suburban Water Systems | CA |
| Suffolk | VA |
| Sun ‘n Lake of Sebring Improvement District | FL |
| Sunny Slope County Water District | CA |
| Sunnyvale | CA |
| Sunrise | FL |
| Sunrise Water Authority | OR |
| SunWater | Australia |
| Superior Water, Light and Power Company | WI |
| Surrey | Canada |
| Sutton and East Surrey Water Plc | United Kingdom |
| Sweetwater Authority | CA |
| T.M.V.W. | Belgium |
| Tacoma | WA |
| Talent | OR |
| Tallahassee | FL |
| Tampa | FL |
| Tampa Bay Water | FL |
| Tamworth City Council | Australia |
| Tasman District Council | New Zealand |
| Taupo District Council | New Zealand |
| Tauranga District Council | New Zealand |
| Tea Acque srl | Italy |
| Teidagua | Spain |
| Teignbridge District Council | United Kingdom |
| Telford & Wrekin Council | United Kingdom |
| Tendring District Council | United Kingdom |
| Texarkana Water Utilities | TX |
| Thames Coromandel District Council | New Zealand |
| Thames Water Utilities Ltd | United Kingdom |
| The City and County of Swansea | United Kingdom |
| The Dalles | OR |
| The Ohio State University | OH |
| Thornton | CO |
| Thorold, Ontario | Canada |
| Thousand Oaks | CA |
| Thunder Bay | Canada |
| Thurston County Public Works | WA |
| Timaru District Council | New Zealand |
| Timmins, Ontario | Canada |
| Tinker Air Force Base | OK |
| TMVW, Gent | Belgium |
| Toledo | OH |
| Torbay Council | United Kingdom |
| Torfaen Borough Council | United Kingdom |
| Toronto, Ontario | Canada |
| Torrance | CA |
| Town of Andover | MA |
| Town of Apple Valley | CA |
| Town of Cary | NC |
| Town of Chestermere, Alberta | Canada |
| Town of Concord | MA |
| Town of Crested Butte | CO |
| Town of East Lyme | CT |
| Town of Estes Park | CO |
| Town of Exeter | NH |
| Town of Flower Mound | TX |
| Town of Fort Erie, Ontario | Canada |
| Town of Gilbert | AZ |
| Town of Grimsby, Ontario | Canada |
| Town of Hilton Head Island | SC |
| Town of Ipswich | MA |
| Town of Leesburg | VA |
| Town of Lincoln, Ontario | Canada |
| Town of Meredith | NH |
| Town of Niagara-on-the-Lake, Ontario | Canada |
| Town of Niskayuna | NY |
| Town of Peace River, Alberta | Canada |
| Town of Pelham, Ontario | Canada |
| Town of Plymouth | MA |
| Town of Prescott Valley | AZ |
| Town of Queensbury | NY |
| Town of Reading | MA |
| Town of Ridgeland | SC |
| Town of Smithfield | RI |
| Town of Smyrna | TN |
| Town of Tewksbury | MA |
| Town of Vestal | NY |
| Town of Yarmouth | MA |
| Township of Langley | Canada |
| Trabuco Canyon Water District | CA |
| Trafford Borough Council | United Kingdom |
| TRANSCO | UAE |
| Tri-County Water | CO |
| Troy | OH |
| Truckee Meadows Water Authority | NV |
| Truckee Sanitary District | CA |
| Truckee-Donner Public Utilities | CA |
| Tualatin | OR |
| Tualatin Valley Water District | OR |
| Tucker, Young, Jackson, Tull, Inc. | MI |
| TUCRAIL SA/NV | Belgium |
| Tucson | AZ |
| Tumut Shire Council | Australia |
| Tumwater | WA |
| Tuolumne Utilities District | CA |
| Tustin | CA |
| Tweed Shire Council | Australia |
| Ujung Pandang | Indonesia |
| UNIGAS | Italy |
| Union Sanitary District | CA |
| Union Water Supply System | Canada |
| United States Department of Agriculture | AR |
| United Utilities Australia Pty, Ltd. | Australia |
| United Utilities Water Plc | United Kingdom |
| United Water | Australia |
| United Water | NJ |
| Unitywater | Australia |
| University of California Davis Water Utility | CA |
| University of Texas Utilities & Energy Management | TX |
| University of Utah | UT |
| University Park | TX |
| Upland | CA |
| Upper Hutt City Council | New Zealand |
| Urbandale | IA |
| US Air Force 153 - Scott Air Force Base | IL |
| US Air Force European Command | Germany |
| US Army Corps of Engineers | AL |
| US Army Fort Richard | AK |
| US Army Garrison | HI |
| US Army Garrison Alaska | AK |
| US Army Transportation Center - Fort Eustis | VA |
| USAID West Bank and Gaza | Palestine |
| USDA - NRCS | ID |
| USDA - NRCS | UT |
| Utah Division of Drinking Water | UT |
| V i K´ AD - Lovetch | Bulgaria |
| VaK Pardubice a.s. | Czech Republic |
| Vale of Glamorgan DC | United Kingdom |
| Vallecito Water Company | CO |
| Vallejo | CA |
| Valley Center Municipal Water District | CA |
| Vance AFB | OK |
| Vancouver | Canada |
| Vancouver | WA |
| Vaughan | Canada |
| Velio Water, China | China |
| Venice | FL |
| VENLO Gemeente | Netherlands |
| Ventura Regional Sanitation District | CA |
| Ventura Water | CA |
| Veolia Eau | France |
| Veolia Water Central Limited | United Kingdom |
| Veolia Water Indianapolis | IN |
| Vera Water & Power | WA |
| Vernon | CA |
| Versailles | OH |
| Victor | ID |
| Victor Valley Water District | CA |
| Victoria | Canada |
| Vik Pernik | Bulgaria |
| Village of Algonquin | IL |
| Village of Endicott | NY |
| Village of Fredonia | NY |
| Village of Howard | WI |
| Village of Lake Zurich | IL |
| Village of Mount Prospect | IL |
| Village of Pleasant Prairie | WI |
| Ville de Quebec | Canada |
| Virginia Beach | VA |
| Visalia | CA |
| Vista Irrigation District | CA |
| Vitens | Netherlands |
| VITO | Belgium |
| VIVAQUA | Belgium |
| VLM | Belgium |
| VMM | Belgium |
| VMM Afdeling Water | Belgium |
| Waco | TX |
| WAF | Fiji |
| Waimate District Council | New Zealand |
| Waipa District Council | New Zealand |
| Waitakere City Council | New Zealand |
| Waitaki District Council | New Zealand |
| Wakefield Public Works | MA |
| Walla Walla | WA |
| Walnut Valley Water District | CA |
| Wanganui District Council | New Zealand |
| Warren | OH |
| Warren Air Force Base | WY |
| Warwick District Council | United Kingdom |
| Washington Water Service Company | WA |
| Wasilla | AK |
| Water & Sewerage Authority of Trinidad & Tobago | West Indies |
| Water and Sewer Authority of Cabarrus County | NC |
| Water Authority of Fiji | Fiji |
| Water Authority of Jordan | Jordan |
| Water Corporation | Australia |
| Water Directorate in Eastern Region (Dammam) – MOWE | Saudi Arabia |
| Water Management Group | CA |
| Water Pollution Control Authority of Norwalk | CT |
| Water Users, LLC | AR |
| Watercare Services, Ltd. | New Zealand |
| Waternet | Netherlands |
| WaterOne | KS |
| Waterschap de Dommel | Netherlands |
| Waterschapsbedrijf Limburg | Netherlands |
| Watsonville | CA |
| Waveney District Council | United Kingdom |
| We Energies | WI |
| Weber Basin Water Conservancy District | UT |
| WEERT | Netherlands |
| Welland, Ontario | Canada |
| Wellington | FL |
| Wellington City Council | New Zealand |
| Welsh Water | United Kingdom |
| Wessex Water Services Ltd | United Kingdom |
| West Basin | CA |
| West Bend | WI |
| West Bloomfield Charter Township | MI |
| West County Wastewater District | CA |
| West Des Moines Water Works | IA |
| West Dorset District Council | United Kingdom |
| West Jordan | UT |
| West Lincoln, Ontario | Canada |
| West Linn | OR |
| West Melbourne | FL |
| West Palm Beach | FL |
| West Sacramento | CA |
| West Valley Sanitation District | CA |
| West Valley Water District | CA |
| Western Bay of Plenty District Council | New Zealand |
| Western Municipal Water District | CA |
| Western Virginia Water Authority | VA |
| Western Water | Australia |
| Westmeath County Council | Ireland |
| Westminster | CA |
| Westminster | CO |
| Weston | MA |
| Whakatane District Council | New Zealand |
| Whangarei District Council | New Zealand |
| Whitby, Ontario | Canada |
| White House Utility District | TN |
| Whiteman Air Force Base | MO |
| Wichita Falls | TX |
| Wichita Water & Sewer Department | KS |
| Wicklow County Council | Ireland |
| Wide Bay Water | Australia |
| Wigan Metropolitan Borough Council | United Kingdom |
| Wilmington | DE |
| Wilsonville | OR |
| Winchester Municipal Utilities | KY |
| Wingecarribee Shire Council | Australia |
| Winkler | Canada |
| Winter Park | FL |
| Wisconsin Electric | WI |
| WML | Netherlands |
| WML Limburgs Drinkwater | Netherlands |
| WMLC - Florida Park | South Africa |
| Woburn | MA |
| Woodinville Water District | WA |
| Woodland | CA |
| Woodmoor Water & Sanitation District | CO |
| Wyoming | MI |
| Yarra Valley Water Authority | Australia |
| Yorba Linda Water District | CA |
| York County | SC |
| York, Regional Municipality of | Canada |
| Yorkshire Water | United Kingdom |
| Yosemite National Park | CA |
| Yuba City | CA |
| Yucaipa Valley Water District | CA |
| Yuma | AZ |
| Yuma Marine Corp Air Station | AZ |
| Zeehaven IJmuiden NV | Netherlands |
| Zhejiang Design Institute of Water Conservancy and Hydroelectric Power | China |
| Zone 7 Water Agency | CA |
| Zwolle gemeente | Netherlands |