An eligible political subdivision may not sell or incur obligations to fund an economic development program established under authority granted by Section 15.980 that are payable in whole or in part from ad valorem taxes unless the residents of the political subdivision, voting at an election held for the purpose, approve the issuance of obligations to fund an economic development program for the provision of loans or grants to persons to construct projects that will conserve and develop the water resources of the political subdivision for the ultimate benefit of the public and assist in developing and diversifying the local economy.
Tex. Water Code § 15.981