Every municipality is and any two or more municipalities acting jointly, whether situate in the same county or different counties, are, hereby empowered and authorized to construct, reconstruct, establish, acquire, improve, renovate, extend, enlarge, increase, own, equip, repair (including replacements), maintain and operate any municipal public works, together with all appurtenances necessary, appropriate, useful, convenient or incidental for or to the maintenance and operation of such works, and shall have plenary power and authority to acquire by gift, grant, purchase, condemnation or otherwise, and thereafter hold, all necessary lands, rights, easements, right-of-ways, franchises and other property therefor within or without, or partly within and partly without, the corporate limits of any such municipality or municipalities, and to issue revenue bonds to pay the costs of such public works and properties: Provided, That this section shall not be construed to authorize any municipality to construct, reconstruct, establish, acquire, improve, renovate, extend, enlarge, increase, own, equip, repair (including replacements), maintain or operate any works which would render a service already being adequately rendered within such municipality. No obligation shall be incurred by any municipality in such construction, reconstruction, establishment, acquisition, improvement, renovation, extension, enlargement or increase, except such as is payable solely from the funds provided under the authority of this article.