Section 12. (a) In order to provide for the collection and enforcement of fees, rates, rents, assessments and other charges for the operation of any water pollution abatement project, the system of which it is a part and any other revenue producing facilities from which the local governmental unit derives local system revenues, in addition to any other authority provided by law or any applicable bond act, local governmental units are hereby granted all the powers and privileges granted to them by the General Laws with respect to any similar fee, rate, rent, assessment or other charge. Without limiting the generality of the foregoing, local governmental units shall have the powers and be subject to the limitations to the extent applicable and consistent with this chapter provided in sections forty-two A to forty-two F, inclusive, of chapter forty, whether or not said sections have been accepted by the local governmental unit, and chapters sixty, eighty and eighty A.

(b) Any local governmental unit may enter into agreements with the trust or the department regarding the operation of a pricing system for the services provided by any water pollution abatement project, the system of which it is a part and any other revenue producing facilities from which the local governmental unit derives local system revenues. Such agreements may include without limitation provisions defining the costs of such services, the water pollution abatement project and such local system and other facilities, and covenants or agreements regarding the fixing and collection of fees, rates, rents, assessments and other charges for such costs and the maintenance of such pricing system at levels sufficient to pay or provide for all such costs and any payments due the trust under any loan agreement or local governmental obligations.

(c) Any local governmental unit may enter into agreements with the trust and the department regarding the operation of an enterprise fund established for any water pollution abatement project, the system of which it is a part and any other revenue producing facilities from which the local governmental unit derives local system revenues. Such agreements may include without limitation fiscal and accounting controls and procedures, provisions regarding the custody, safeguarding and investment of local system revenues and other amounts credited thereto, the establishment of reserves and other accounts and funds and the application of any surplus funds.

(d) Any local governmental unit may or, in the case of a regional local governmental unit, any city, town, board, commission or other instrumentality which is a member or other service recipient thereof may (i) for furnishing wastewater services, establish rates, rents, fees, assessments and other charges on the basis of a flat rate per volume of wastewater processed or on the basis of ascending unit rates based on the quantity or strength of wastewater processed and (ii) provide for furnishing wastewater services in its charges or through abatement proceedings conducted in accordance with its regulations for assurance of service to persons who by reason of age, infirmity or poverty are unable to pay the charges otherwise applicable, provided that the aggregate liability of the local governmental unit or such member or other service recipient for amounts attributable to any loan or local governmental obligations shall be in no way diminished thereby. Any local governmental unit and any such member or other service recipient which raises all or any part of the cost of wastewater services or any assessment therefor through real and personal property taxes assessed by the local governmental body shall indicate on the tax bills furnished to each taxpayer the portion of the tax assessed for such services.