The incident occurred when the victims, most of them pilgrims taking part in the ongoing Urs festivities at the local Dargah, had gone near the tank in the morning, police said.
The injured are being treated at a local hospital, they added.
According to district administration officials, the tank was built under a Gram Panchayat programme and poor quality of construction was blamed for its collapse.
Stating that district administration is investigating the cause, officials said a criminal case had been booked against those responsible.