In case where a health officer has been appointed under the provisions of N.H. Rev. Stat. § 128:6 for several towns, such officer may, subject to the approval of the selectmen of the several towns and the commissioner of the department of health and human services, appoint a deputy health officer or officers who shall be empowered to enforce public health laws and regulations and make such sanitation investigations as said health officer may direct or as may be required by the department of health and human services. Said deputy health officer shall receive such compensation from each town as the selectmen thereof or the town shall fix.