(a) On or before July 1, 1990, each public or private water company serving one thousand or more persons shall map at level B all areas of contribution and recharge areas for its existing wells located in stratified drift aquifers. Not later than three years after the adoption by the Commissioner of Energy and Environmental Protection of a model municipal aquifer protection ordinance under § 22a-354l, each public and private water company serving ten thousand or more persons shall map at level A all areas of contribution and recharge areas for its existing wells located in stratified drift aquifers. Any public or private water company that creates a new well field serving one thousand or more persons that has not been mapped previously as an existing well shall map areas of contribution and recharge areas for the new well field. Any map of such a new well field shall be submitted not later than one year after the issuance of a diversion permit in accordance with § 22a-368 at level B, and not later than three years after the issuance of a diversion permit in accordance with § 22a-368 at level A. The Commissioner of Energy and Environmental Protection may map at level A and at level B all areas of contribution and recharge areas for existing wells located in stratified drift aquifers that are used by any public or private water company serving less than one thousand persons.

(b) Each public or private water company serving ten thousand or more persons shall map all areas of contribution and recharge areas for potential wells that are located within stratified drift aquifers identified as future sources of water supply to meet their needs in accordance with the plan submitted pursuant to § 25-33h at level B not more than two years after the Commissioner of Energy and Environmental Protection requests such mapping. The Commissioner of Energy and Environmental Protection shall identify and make recommendations for mapping, or shall map, all remaining significant areas of contribution and recharge areas for potential wells located in stratified drift aquifers not identified by a public or private water company as a potential source of water supply within the region of an approved plan. Mapping of any other area of contribution and recharge areas for potential wells located in stratified drift aquifers by the commissioner shall be completed at a time determined by the commissioner.