The Water Resources Department, formerly known as the Irrigation Department, is one of the major establishments of the Government of Bihar. This safeguards the rights of the states in sharing the waters of the inter-state rivers/basins. Creation of irrigation potential and utilization of created capacity through construction, maintenance and regulation of major and medium irrigation schemes, construction and maintenance of embankments, reconstruction in selected part of river banks, ground levelling and other necessary flood protection works. 

The department aims to provide maximum benefits of various irrigation projects to the beneficiary societies through administrative control and rigorous monitoring system. Government of Bihar has launched Har Khet Tak Sinchai ka Paani Yojana,  under this scheme the government has planned to focus on minor irrigation projects and this year work will be done on 184 minor irrigation projects which will impact close to 22000 hectare area. Target is to make Bihar Atmanirbhar by 2025 under “Saat Nishchay -II” program of the government and one of the key objective is to make irrigation water available to every farm.