Water level in Bagmati river in Darbhanga increased on Tuesday due to rainfall in the region.
Incessant rains in north Bihar have affected around 10 lakh families with water breaching the river banks at numerous places.
Food packets and relief material are already being airdropped in the affected areas.
Around 50 dwelling units in Naruar village of Madhubani district were destroyed due to floods on July 23.
Residents of Kakarghatti village in Darbhanga were earlier forced to set up temporary shelters on the National Highway 57 after floodwater entered their houses and farms.
Around 12 districts including Sheohar, Dharbangha, Sitamarhi, North Champaran, Madhubani, Araria, and Kishanganj have been severely affected due to floods.
On July 19, Chief Minister Nitish Kumar had kickstarted the process of sending cash relief of Rs 6,000 directly into the bank accounts of flood-affected families.
However, several people living in flood-hit areas have claimed that they have not received any aid from the government.