Tokyo Metropolitan Government
http://www.metro.tokyo.jp/ENGLISH/index.htm

Bureau of Waterworks, Tokyo Metropolitan Government
http://www.waterprofessionals.metro.tokyo.jp/
http://www.waterworks.metro.tokyo.jp/eng/index.html

Ministry of Land, Infrastructure, Transport and Tourism
http://www.mlit.go.jp/index_e.html

Japan Sewage Works Association
http://www.jswa.jp/en/jswa-en/