a. (1) The commissioner is authorized to install or cause to be installed water meters, the pattern and maximum price of which shall be approved by the board of estimate in any or all stores, workshops, hotels, lodging houses, factories, office buildings, and public edifices, at wharves, ferry houses, and stables, and in all places in which water is furnished for business consumption and in any or all new or substantially improved or altered dwellings. When authorized thereto by resolution of the board of estimate or by local law, the commissioner may install such meters in any or all other multiple dwellings, and he or she shall install such meter or meters or cause them to be installed upon written demand of the owner of any lot or premises to which such water is supplied.
(2) For purposes of this subdivision an improvement or alteration is a physical change in an existing structure, other than painting, ordinary repairs and normal replacement of maintenance items. A structure shall be deemed to have been substantially improved or altered where:
(a) the cost of improvement or alteration exceeds the sum of one hundred fifty thousand dollars; or
(b) fifty percent or more of the dwelling units or square feet of the structure in multiple dwellings are improved or altered and the cost of such improvement or alteration exceeds the sum of fifteen thousand dollars per dwelling unit; or
(c) there has been a conversion in the use of the structure.
b. Thereafter, as shall be determined by the commissioner, the department shall make out all charges for water furnished by such department to such premises in ratable proportion to the water furnished, as ascertained by meter, subject to such minimum and service charges as may be established. All expense and cost of meters, and their connections, and of their setting, repair and maintenance, unless with the approval of the board of estimate such expense and cost be borne by the department, shall be a charge and lien upon the premises.
c. This section shall not, however, be construed so as to remit or prevent the due collection of arrearages or charges for water consumption heretofore incurred, nor interfere with the proper liens therefor, nor of charges, or rates, or liens hereafter to be incurred for water consumption in any building or place which may not contain one of the meters aforesaid. The moneys collected for service charges and for expense and cost of meters and their connections, and for setting, repairing, maintaining and replacing the same, may be applied by the commissioner to the payment of expenses incurred in procuring meters and their connections and in their setting, repair, maintenance and replacement.