Tex. Health & Safety Code § 61.010

If the governing body of a governmental entity adopts a property tax rate that exceeds the rate calculated under Section 26.04, Tax Code, by more than eight percent, and if a portion of the tax rate was designated to provide revenue for indigent health care services required by this chapter, the revenue produced by the portion of the tax rate designated for that purpose may be spent only to provide indigent health care services.