Rail traffic has been disrupted at several places due to overtopping of rail tracks at many places.
The weather department has forecast heavy rainfall for the city till September 30.
The MET department has also predicted torrential rains in 19 districts including Gopalganj, Purnea, Katihar Buxar.
The Patna district administration has ordered closure of all schools till Tuesday.
Meanwhile, three teams of NDRF were deployed in Patna and three more have been mobilised.
SDRF teams have also been pressed into service in districts which have received heavy rainfall.
Boats have also been pressed into service for affected people.
The state government has established a State Emergency Operation Centre to coordinate with the rescue and relief work.