Omm Sai Infotech — How to calculate water bill when we aren't a rented or lease house

Address:

Gurumurthy road kammanhalli, Bangalore, Karnataka

Here water bill comes only 390 per month they are charging with us 500 per month. Only 3 houses including owner. So i need a confirmation on this tell them to share it for 3 houses and pay. They are charging 500 rs permonth. Pl tell them anybody next when they give a bill.