Tex. Local Government Code § 271.056

The provisions of this subchapter relating to the advertisement for competitive bids do not apply to:

(1) a case of public calamity if it is necessary to act promptly to relieve the necessity of the residents or to preserve the property of the issuer;

(2) a case in which it is necessary to preserve or protect the public health of the residents of the issuer;

(3) a case of unforeseen damage to public machinery, equipment, or other property;

(4) a contract for personal or professional services;

(5) work done by employees of the issuer and paid for as the work progresses;

(6) the purchase of any land, building, existing utility system, or right-of-way for authorized needs and purposes;

(7) expenditures for or relating to improvements in municipal water systems, sewer systems, streets, or drainage, if at least one-third of the cost of the improvements is to be paid by special assessments levied against properties to be benefitted by the improvements;

(8) a case in which the entire contractual obligation is to be paid from bond funds or current funds or in which an advertisement for bids has previously been published in accordance with this subchapter but the current funds or bond funds are not adequate to permit the awarding of the contract and certificates are to be awarded to provide for the deficiency;

(9) the sale of a public security, as that term is defined by Section 1204.001, Government Code;

(10) a municipal procurement of a kind that, under Chapter 252, is not required to be made in accordance with competitive bidding procedures like those prescribed by this subchapter; or

(11) a county contract that, under the County Purchasing Act (Subchapter C, Chapter 262), is not required to be made in accordance with competitive bidding procedures like those prescribed by this subchapter.