The deceased were identified as Prakash, Yakosava and Subbaiah, all hailing from Andhra Pradesh, police said.
The victims were engaged in the construction of a multi-storeyed building.
The heavy downpour inundated the low-lying areas and water gushed in to the houses.
A pedestrian was injured in Indiranagar area when a tree fell on him. Movement of vehicular traffic was badly affected with rain water flooding the roads.