Relating to the authority of a county commissioners court to adopt an exemption from ad valorem taxation by each taxing unit that taxes the property of the portion of the appraised value of a person's property that is attributable to the installation in or on the property of certain water conservation systems.

HB 3637 allows Texas counties to create property tax exemptions for the portion of a home’s value tied to qualifying water conservation systems, such as rainwater harvesting or graywater systems. Homeowners who install these systems would see reduced property taxes, with the exemption applying to all taxing entities (like cities, school districts, and counties) that collect taxes on the property. The county commissioners court must adopt the exemption via order, and it would only take effect for tax years starting January 1, 2026, if voters approve a related constitutional amendment. This policy directly affects property owners installing eligible systems and the taxing units collecting taxes on those properties.