---identifier: "/us/cfr/t43/s426.21"source: "ecfr"legal_status: "authoritative_unofficial"title: "43 CFR § 426.21 - Interest on underpayments."title_number: 43title_name: "Public Lands: Interior"section_number: "426.21"section_name: "Interest on underpayments."chapter_name: "BUREAU OF RECLAMATION, DEPARTMENT OF THE INTERIOR"part_number: "426"part_name: "ACREAGE LIMITATION RULES AND REGULATIONS"positive_law: falsecurrency: "2026-03-24"last_updated: "2026-03-24"format_version: "1.1.0"generator: "[email protected]"authority: "5 U.S.C. 301; 5 U.S.C. 553; 16 U.S.C. 590z-11; 31 U.S.C. 9701; and 32 Stat. 388 and all acts amendatory thereof or supplementary thereto including, but not limited to, 43 U.S.C. 390aa to 390zz-1, 43 U.S.C. 418, 43 U.S.C. 423 to 425b, 43 U.S.C. 431, 434, 440, 43 U.S.C. 451 to 451k, 43 U.S.C. 462, 43 U.S.C. 485 to 485k, 43 U.S.C. 491 to 505, 43 U.S.C. 511 to 513, and 43 U.S.C. 544."regulatory_source: "61 FR 66805, Dec. 18, 1996, unless otherwise noted."cfr_part: "426"---
Identifier
/us/cfr/t43/s426.21
Currency
2026-03-24
Positive Law
No
Updated
2026-03-24
Chapter
Bureau of Reclamation, Department of the Interior
Authority
5 U.S.C. 301; 5 U.S.C. 553; 16 U.S.C. 590z-11; 31 U.S.C. 9701; and 32 Stat. 388 and all acts amendatory thereof or supplementary thereto including, but not limited to, 43 U.S.C. 390aa to 390zz-1, 43 U... 5 U.S.C. 301; 5 U.S.C. 553; 16 U.S.C. 590z-11; 31 U.S.C. 9701; and 32 Stat. 388 and all acts amendatory thereof or supplementary thereto including, but not limited to, 43 U.S.C. 390aa to 390zz-1, 43 U.S.C. 418, 43 U.S.C. 423 to 425b, 43 U.S.C. 431, 434, 440, 43 U.S.C. 451 to 451k, 43 U.S.C. 462, 43 U.S.C. 485 to 485k, 43 U.S.C. 491 to 505, 43 U.S.C. 511 to 513, and 43 U.S.C. 544.
# 426.21 Interest on underpayments.(a) *Definition of underpayment.* For the purposes of this section *underpayment* means the difference between what a landholder owed for the delivery of irrigation water under Federal reclamation law and what that landholder paid.(b) *Collection of interest on underpayments.* If a landholder has incurred an underpayment, Reclamation will collect from the appropriate district such underpayment with interest. Interest accrues from the original payment due date until the district pays the amount due. The original payment due date is the date the district should have paid the United States for water delivered to the landholder.(c) *Underpayment interest rate.* The Secretary of the Treasury determines the interest rate charged the district based on the weighted average yield of all interest-bearing marketable issues sold by the Department of the Treasury during the period of underpayment.