(b) Any such agreement shall include a provision for the construction of the facility, either by the municipality or by the state on behalf of the municipality, in accordance with plans approved by the commissioner, and any such agreement shall include a provision requiring operation and maintenance of the facility by the municipality.

(c) In any such agreement the state may agree, within amounts appropriated therefor as allocated by the director of the budget, to pay to the municipality an amount to be determined by the commissioner not to exceed the lesser of (1) seventy-five per cent of the cost of the facility, less any federal assistance received or to be received for the facility and (2) fifty per cent of the cost of the facility; except that when the facility is constructed by the state on behalf of the municipality, the municipality shall agree to reimburse the state in an amount to be determined by the commissioner not to be less than the cost of the facility less the sum of (1) any federal assistance received or to be received for the facility and (2) the lesser of (i) seventy-five per cent of the cost of the facility, less any federal assistance received or to be received for the facility and (ii) fifty per cent of the cost of the facility. Whenever two or more municipalities agree to participate in a project, such municipalities, by agreement with the commissioner and each other, shall agree to an equitable sharing of the local share of the cost of the project.

(d) In the event a municipality shall fail to pay to the state the municipality's share of the cost of a facility constructed by the state on behalf of the municipality within six months of the certification to the municipality by the state comptroller of the amount of such share, the state comptroller shall cause to be withheld from state assistance to which such municipality would otherwise be entitled, a sum sufficient to reimburse the state for any amount remaining unpaid, together with interest on any such unpaid amount at the rate of three per cent per annum from the date of such certification. Monies so withheld shall be credited against the amount of principal and interest payable by such municipality for its share of the cost of the facility.