"(4) If a drain or related service connection or part thereof is found on investigation by a water services authority not to be inadequate, defective, foul or neglected or to permit the infiltration or exfiltration of water or waste water, but it appears to the water services authority that any separate premises drained by such system or part thereof is not drained satisfactorily, the water services authority may serve notice on the owner in accordance with section 42, or may provide or contribute to the cost of providing drainage for the premises.