In connection with any housing project, located wholly or partly within the area in which it is authorized to act, any city, borough, town, township or county may contract with a housing authority or the Federal Government with respect to any sums which the housing authority or the Federal Government may agree to pay during any year or period of years to the city, borough, town, township or county for the improvements, services, and facilities to be provided by it for the benefit of said housing project, or the persons residing on or occupying such premises; but in no event shall the amount of such payments exceed the estimated cost to the city, borough, town, township or county of the improvements, services or facilities to be so supplied: Provided, however, That the absence of a contract for such payments shall in no way relieve cities, boroughs, towns, townships, and counties from the duty to furnish, for the benefit of said housing project and the persons residing on or occupying said premises, customary improvements and such services and facilities as cities, boroughs, towns, townships, and counties, respectively, usually furnish without a service fee.