Tex. Local Government Code § 262.023

(a) Before a county may purchase one or more items under a contract that will require an expenditure exceeding $100,000, the commissioners court of the county must:

(1) comply with the competitive bidding or competitive proposal procedures prescribed by this subchapter;

(2) use the reverse auction procedure, as defined by Section 2155.062(d), Government Code, for purchasing; or

(3) comply with a method described by Chapter 2269, Government Code.

(b) The requirements established by Subsection (a) apply to contracts for which payment will be made from current funds or bond funds or through anticipation notes authorized by Chapter 1431, Government Code, or time warrants. Contracts for which payments will be made through certificates of obligation are governed by The Certificate of Obligation Act of 1971 (Subchapter C, Chapter 271).

(b-1) A county that complies with a method described by Chapter 2269, Government Code, as provided by Subsection (a)(3), to enter into a contract for which payment will be made through anticipation notes authorized by Chapter 1431, Government Code, may not issue anticipation notes for the payment of that contract in an amount that exceeds the lesser of:

(1) 20 percent of the county's budget for the fiscal year in which the county enters into the contract; or

(2) $10 million.

(c) In applying the requirements established by Subsection (a), all separate, sequential, or component purchases of items ordered or purchased, with the intent of avoiding the requirements of this subchapter, from the same supplier by the same county officer, department, or institution are treated as if they are part of a single purchase and of a single contract. In applying this provision to the purchase of office supplies, separate purchases of supplies by an individual department are not considered to be part of a single purchase and single contract by the county if a specific intent to avoid the requirements of this subchapter is not present.