Texas Government Code - GOV'T § 1474.101. Limit on Debt

(a) If a county contains one or more districts organized under Section 52, Article III, or Section 59, Article XVI, Texas Constitution, the ratio of the debt of a district to the assessed value of real property in the district, expressed as a percentage, together with the ratio of the proposed county debt to the assessed value of real property in the county, expressed as a percentage, may not exceed one-fourth of the assessed value of real property in the county or in the district.

(b) The assessed value of real property in a county or in a district is computed according to the most recent appraisal roll of the county or district, as appropriate.