Tax Code §6.036

(a) An individual is not eligible to be appointed to or to serve on the board of directors of an appraisal district if the individual or a business entity in which the individual has a substantial interest is a party to a contract with: (1) the appraisal district; or (2) a taxing unit that participates in the appraisal district, if the contract relates to the performance of an activity governed by this title. (b) An appraisal district may not enter into a contract with a member of the board of directors of the appraisal district or with a business entity in which a member of the board has a substantial interest. (c) A taxing unit may not enter into a contract relating to the performance of an activity governed by this title with a member of the board of directors of an appraisal district in which the taxing unit participates or with a business entity in which a member of the board has a substantial interest. (d) For purposes of this section, an individual has a substantial interest in a business entity if: (1) the combined ownership of the individual and the individual's spouse is at least 10 percent of the voting stock or shares of the business entity; or (2) the individual or the individual's spouse is a partner, limited partner, or officer of the business entity. (e) In this section, "business entity" means a sole proprietorship, partnership, firm, corporation, holding company, joint-stock company, receivership, trust, or other entity recognized by law. (f) This section does not limit the application of any other law, including the common law relating to conflicts of interest, to an appraisal district director.