| Event |
| ASPIRE TOKYO 2011 |
| Water utilities |
| Otaru City Water Works Department |
| Hachinohe Regional Water Supply Authority |
| Bureau of Waterworks, Tokyo Metropolitan Government |
| Yokohama Waterworks Bureau |
| Chiba Prefectural Waterworks Bureau |
| Nagoya City Waterworks & Sewerage Bureau |
| Joetsu City Gas & Water Utilties Bureau |
| Kyoto City Waterworks & Sewerage Bureau |
| Osaka City Waterworks Bureau |
| Sakai City Waterworks & Sewerage Bureau |
| Hiroshima City Waterworks Bureau |
| Okinawa Prefectural Enterprise Bureau |
| National water-related authorities |
| Water Supply Division, Health Service Bureau, Ministry of Health, Labour and Welfare Water Supply in Japan |
| Ministry of Internal Affairs and Communications |
| Land and Water Bureau, Ministry of Land, Infrastructure, Transport and Tourism |
| Ministry of the Environment |
| Japan Water Agency |
| National Institute of Public Health |
| O & M Network |
| National Institute of Environmental Studies |
| Japan Water Research Center |
| Assistance to developing countries/international exchange |
| Japan International Cooperation Agency, JICA |
| Council of Local Authorities of International Relation, CLAIR |
| Japan Water Forum, JWF |
| Wastewater organizations/water environment societies |
| Japan Sewage Works Association |
| Japan Society on Water Environment |
| Urban Environment Engineering Course, Department of Urban Engineering, Graduate School of Engineering, The University of Tokyo |
| Kyoto University Graduate School of Global Environmental Studies |
| International Water Association |
IWA Japan National Committee |
| IWA |
