Any owner desiring to voluntarily upgrade an onsite or alternative discharging sewage system that is not failing shall file an application, according to instructions from the Board, to obtain a construction permit to improve the system in accordance with the laws and regulations of the Board for repairing failing systems, provided such upgrade is for the purposes of reducing threats to the public health, or to ground and surface waters, including the reduction of nitrogen discharges. The Department shall attach a statement to any permit issued pursuant to this section clearly stating that the upgrades specified in the permit are voluntary and not required by law. The Department may require the owner to indemnify and hold harmless the Department prior to the issuance of any such permit. Any permits issued pursuant to this section shall be subject to the provisions of § 32.1-164.1:1.