30 Tex. Admin. Code § 37.51
An owner or operator may use a financial assurance mechanism as specified in this chapter to meet the requirements of this chapter for more than one facility, provided that the facilities are in the same program area. Financial assurance submitted to the executive director shall include a list showing for each facility covered by the mechanism: the name, physical and mailing addresses of the facility, each program area and permit number, the rules regulating the program under which the facility is permitted, and the amount of funds demonstrated for each permit, for closure, post closure, corrective action, and liability. The amount of funds available through the mechanism must be no less than the sum of funds that would be available if a separate mechanism had been established and maintained for each facility. In directing funds available through the mechanism for any of the facilities covered by the mechanism, the executive director may call on only the amount of funds designated for that facility, unless the owner or operator agrees to the use of additional funds available under the mechanism.
30 Tex. Admin. Code § 37.51