What will be the lifespan of a borewell and rainwater harvesting ringwell around the borewell ?


We are a housing society in Parel, Mumbai. In may 2019, we drilled a borewell until 250 ft and got 2.5 inch water, reasonably good quality with tds 1100. We dug a ringwell around this borewell (19 feet depth), and connected our terrace (4000 sqft) and podium (10000 sqft) to this ringwell. After few days of rain, tds was found 475, possibly due to dilution of water. Earlier, we were calling two tankers a day. We installed a softener plant and are using this borewell water for bathroom and flush purpose. Our tankers have stopped since 20th August 2019.(we were spending 80000 per month) My question is: How long will this borewell continue to give us water? As of now the flow is tremendous and we will recharge it with rainwater every year

Nimesh Shah