Tex. Educ. Code § 49.201
The board of trustees of a district with a local revenue level in excess of entitlement may execute an agreement to educate the students of another district in a number that, when the weighted average daily attendance of the students served is added to the weighted average daily attendance of the contracting district, is sufficient, in combination with any other actions taken under this chapter, to reduce the district's local revenue level to a level that is equal to or less than the level established under Section 48.257. The agreement is not effective unless the commissioner certifies that the transfer of weighted average daily attendance will not result in any of the contracting districts' local revenue level being greater than the level established under Section 48.257 and that the agreement requires an expenditure per student in weighted average daily attendance that is at least equal to the amount per student in weighted average daily attendance required under Section 49.153.
Tex. Educ. Code art. 49.201