The provisions of Sections 1503 and 1504 will be applicable to any political subdivision which constructs facilities to provide or extend water service or provides or extends such service to any territory theretofore actually being lawfully served by any other political subdivision with facilities designed and constructed to provide the same type of service. The provisions of this section shall not apply to any territory, or portion thereof, which is the subject of any final judgment or litigation pending on the effective date of this section involving any duplication of water service occurring prior to the effective date of this section.