43 C.F.R. § 426.7
(a) Definitions for purposes of this section:
Grantor revocable trust means a trust that holds irrigable land or irrigation land that may be revoked at the discretion of the grantor(s), or terminated by the terms of the trust, and revocation or termination results in title to the land held in trust reverting either directly or indirectly to the grantor(s).
Irrevocable trust means a trust that holds irrigable land or irrigation land and does not allow any individual, including the grantor or beneficiaries, the discretion to decide when or under what conditions the trust terminates, and that upon termination the title to the land held in trust transfers either directly or indirectly to a person(s) or entity(ies) other than the grantor(s).
Otherwise revocable trust means a trust that holds irrigable land or irrigation land and that may be revoked at the discretion of the grantor(s) or other parties, or terminated by the terms of the trust, and revocation or termination results in the title to the land held in trust transferring either directly or indirectly to a person(s) or entity(ies) other than the grantor(s).
(b) Attribution of land held by a trust. The acreage limitation entitlements of a trust are only limited by the acreage limitation entitlements of the trustees, grantors, or beneficiaries to whom land held by the trust must be attributed as provided for in § 426.4. The entitlements of the parties to whom trusted land is attributed are determined according to §§ 426.5, 426.6, and 426.8, and other applicable provisions of Federal reclamation law and these regulations. Reclamation attributes nonexempt land held by a trust to the following parties:
(1) For land held in an irrevocable trust, the land is attributed to the beneficiaries in proportion to their beneficial interest in the trust. However, this attribution is only made if the criteria listed in paragraphs (b)(1) (i) and (ii) of this section are met. If the trust fails to meet any portion of these criteria, Reclamation attributes the land held in the trust to the trustee.
(2) For land held in a grantor revocable trust, the land is attributed to the grantor according to the grantor's acreage limitation status and the land's eligibility immediately prior to its transfer to the trust. However, this attribution is only made if the criteria listed in paragraphs (b)(2) (i), (ii), (iii), and (iv) of this section are met. If the trust fails to meet any portion of these criteria, the land held in trust will be ineligible to receive irrigation water until all of the criteria are met. The only exception is if the trust's and grantor's standard certification or reporting forms indicate that the land held by the trust has been attributed to the trust's grantor(s).
(3) For land held in an otherwise revocable trust, the land is attributed to the beneficiaries in proportion to their beneficial interests in the trust. However, this attribution is only made if the trust meets the criteria specified in paragraph (b)(1) of this section and the trust meets the additional criteria specified in paragraph (b)(2) of this section.
(c) Class beneficiaries. For purposes of identifying beneficiaries, a class of beneficiaries specified within the trust document will be acceptable, as long as the trust document is specific as to the beneficial interest to which each member of the class will be entitled and the members of the class are identifiable.
(d) Application of full-cost rate to land held by grantor revocable trusts. If a grantor revocable trust that meets the criteria specified in paragraph (b)(2) of this section is revised by the grantor in a manner that precludes attribution of the land held in trust to the grantor: