Texas Tax Code - TAX § 6.24. Contracts for Assessment and Collection

(a) The governing body of a taxing unit other than a county may contract as provided by the Interlocal Cooperation Act   1 with the governing body of another unit or with the board of directors of an appraisal district for the other unit or the district to perform duties relating to the assessment or collection of taxes.

(b) The commissioners court with the approval of the county assessor-collector may contract as provided by the Interlocal Cooperation Act with the governing body of another taxing unit in the county or with the board of directors of the appraisal district for the other unit or the district to perform duties relating to the assessment or collection of taxes for the county.  If a county contracts to have its taxes assessed and collected by another taxing unit or by the appraisal district, except as provided by Subsection (c), the contract shall require the other unit or the district to assess and collect all taxes the county is required to assess and collect.

(c) A contract entered into under Subsection (b) may exclude from the taxes the other unit or the district is required to assess and collect taxes the county is required to assess and collect under one or more of the following provisions:

(d) A contract under this section may provide for the entity that collects taxes to contract with an attorney, as provided by Section 6.30 of this code, for collection of delinquent taxes.