Very Old Unpaid Water Bill. How to proceed ?

My father built a house about 27 years back. He had taken a water connection from Jal Nigam. Supply was irregular so he got it disconnected from house end using his own sources shortly after, probably unofficially. I do not exactly know this since i am in a job outstation. There is no water meter available. Water bills also never came for last two decades. My father preserved all bills, there are no water bills. Used underground water which is free. My father expired about 9 years back and hereditarily the house and rest of the property was transferred onto my name with all paperwork complete. A month ago Jal Nigam people visited and said that there was a two decades old outstanding water bill of Rs 8000 or so. They did not hand over anything but asked to settle it or they would take RC action. All action happened during my father's time. Can the Jal Nigam ask me to pay the dues? Is there any kind of obligation on me?