does the store on old connecticut path carry 'borsec' mineral water? (1.5 liter plastic bottle)

The only thing you can do is to check the specialty isles and the imports products, By the name, it appears that what you are looking for is an import item.

I don't know what that is,I only purchased smart/ plain water.

No

I don't recall seeing it in the Normal water aisle with the Poland Springs n such. But definitely check the beverage section in aisle 3. Lots of different natural water, seltzer and juices there.