Fairfield County officials have expressed concerns about the South Central Connecticut Regional Water Authority’s bid to acquire Aquarion Water Co. Worries include the financial impact, and potential rate hikes and the authority’s borrowing capacity. The RWA is preparing bids, with a non-binding offer due in mid-September and a binding bid by mid-October. Eversource, the current owner, is looking to sell Aquarion, which serves 59 towns in Connecticut.