SB 749 proposes changes to the adoption of ad valorem tax rates by certain special purpose districts and establishes voter approval requirements for rates exceeding the voter-approval tax rate. The bill mandates transparency in special purpose district operations by requiring the posting of financial and governance details online. It modifies definitions and procedural rules related to tax rates for specific entities, including junior college districts and hospital districts, and repeals certain sections of the Water Code and Special District Local Laws Code concerning tax rates.