Whenever, at the request of an owner or occupant, a service pipe is provided through which service is not immediately desired, said property owner or occupant shall bear the entire reasonable expense of providing, placing and constructing the service pipe and accessories, but he shall be entitled to a refund whenever water service is begun for such part of the expense as the water-works corporation is hereinbefore required to assume. Such refund shall be the cost of said service pipe and accessories, less depreciation at the rate of three percent per annum for the period which said pipe has been in the ground.