(a) The district may impose an ad valorem tax on all taxable property in the district to:
(1) pay for an improvement project of the types authorized by § 52(b), Article III, and § 59, Article XVI, Texas Constitution; or
(2) secure the payment of bonds issued for a purpose described by Subdivision (1).
(b) The district may not impose an ad valorem tax to pay for an improvement project under this chapter unless the imposition is approved by the voters of the district voting at an election held for that purpose. The board may call an election to approve the imposition of an ad valorem tax to pay for an improvement project under this chapter only if the board receives a petition requesting the election signed by:
(1) more than 51 percent of the record owners of real property in the district subject to taxation; or
(2) owners representing more than 51 percent of the appraised value of real property in the district subject to taxation, as determined by the tax rolls of the appraisal district.