30 Tex. Admin. Code § 222.73
(a) The applicant shall conduct and submit with the application a soils evaluation to identify the soils associated with the proposed site. At least one profile hole per soil type must be included in the evaluation. The applicant shall use soil borings, where appropriate, for enhancement of the profile hole determinations. The profile holes utilized in the site evaluation must be no more than five feet deep, or to the first continuous lateral lithic contact. The evaluation must include the following information:
(4) horizon descriptions shall include:
Source Note:The provisions of this §222.73 adopted to be effective July 5, 2006, 31 TexReg 5308.