Builder not providing drinkable water supply

I have flat in kalher gram panchayat it is in bhiwandi thane, in the society we have connection but the water is salty, we hardly use the salty water, builder providing the tankers but water is not good, people facing skin related disease with it, at the time of purchase builder promissed us that he will provide muncipal water supply, but still from last 3 years no muncipal connection we got, how the society can pressurise for the drinkable water supply? and as a society member how i can help in the process of water connection from muncipal corporation