Water management is the activity of planning, developing, distributing and optimum use of water resources under defined water polices and regulations. It includes: management of water treatment of drinking water, industrial water, sewage or wastewater, management of water resources, management of flood protection, management of irrigation, and management of the water table.
Water supply is the process of self-provision or provision by third parties in the water industry, commonly a public utility, of water resources of various qualities to different users
Source: Renewables 2017 - REN21 (Renewable Energy Police Network for the 21st. Century)