The weather department warned more heavy rain is expected on Thursday in the western coastal state.
Rivers have burst their banks and more than 30,000 people fled their homes.
The state government said late on Wednesday that 13 people had died from drowning and the rest from houses or trees collapsing on them.
A national newspaper said 35 people had died so far across the state. Some 1,856 people were rescued by disaster and Army officials deployed for relief operations.
Vadodara was among the worst affected cities, the press release said.
Electricity connections were badly affected, with some 1,000 villages grappling without power. Images and video released by disaster officials showed them using inflatable boats and tyres to rescue people stranded by surging waters.
Rains cause widespread destruction every year, but experts say climate change is shifting weather patterns and increasing the number of extreme weather events.
The northeastern state of Tripura was hit by floods and landslides last week, with more than 20 people killed.
In neighbouring Bangladesh, downriver from India, floods killed at least 40 people over the same period, with nearly 300,000 residents taking refuge in emergency shelters.
