Operation and Maintenance Network (O&M Network) was originally established by in WHO in 1990 and the Working Group was mandated by the Water Supply and Sanitation Collaborative Council, WSSCC. Mr. Hueb, WHO had played an important role in breeding the O&M Network. After one decade, the coordinator was taken over by National Institute of Public Health, Japan (NIPH) upon the decision at the fifth forum in 2000. From 2006, the O&M Network has been supported by WHO’s unit for Water, Sanitation and Health (WSH) and funded by Ministry of Health,Labour and Welfare,Goverment of Japan(MHLW).

Activities before NIPH of Japan took over are as follows;

• An "initial" Working Group (1988 - 1991)
• Nov. 1988 (The Hague) Informal working session with ESA representatives
• Feb. 1990 (The Hague) Pre-planning meeting
• June 1990 (Geneva) First meeting of the "Initial" Working Group
• Sept 1990 (New Delhi) Meeting on O&M parallel to the meeting of the Council and ESAs
• Feb. 1991 (Geneva) Meeting of the Advisory Committee of the Working Group
• A "tools - producing" Working Group (1991 - 1994)
• Sept 1991 (Oslo) Working Group mandated by the WSS Collaborative Council
• June 1992 (Geneva) Meeting of the Advisory Committee
• June 1993 (Geneva) Meeting of the O&M Working Group
• Sept 1993 (Rabat) Special session on O&M at the Global Forum of the Collaborative Council
• June 1994 (Geneva) Meeting of the O&M Working Group
• An "implementing" Working Group (1995 - 1997, and on-going)
• June 1995 (Geneva) Meeting of the O&M Working Group
• Oct. 1995 (Barbados) Special session on O&M at the Global Forum of the Collaborative Council
• Sept 1996 (New Delhi) Meeting of the O&M Working Group
• Feb. 1997 (Geneva) Core group meeting
• From a Working Group to a Network (1997 - 2000)
• Oct. 1997 (Manila) Special session on O&M at the Global Forum of the Collaborative Council and establishment of the O&M Network
• Feb. 1998 (The Hague) O&M Network meeting
• Nov. 2000 (Iguazu) Handing over the O&M Network to the Institute of Public Health of Japan at the Global Forum in Iguazu, Brazil