29 C.F.R. § 780.405

The exemption provided in section 13(b)(12) for irrigation activities is a direct exemption which depends for its application on its own terms and not on the meaning of “agriculture” as defined in section 3(f). This exemption was added by an amendment to section 13(a)(6) in 1949 to alter the effect of the decision of the U.S. Supreme Court in Farmers Reservoir Company v. McComb, 337 U.S. 755, so as to exclude the type of employees involved in that case from certain requirements of the Act. Congress chose to accomplish this result, not by expanding the definition of agriculture in section 3(f), but by adding a further exemption. In view of this approach, it can well be said that Congress agreed with the Supreme Court's holding that such workers are not employed in agriculture. (Goldberg v. Crowley Ridge Assn., 295 F. 2d 7.) Irrigation workers who are employed in any workweek exclusively by a farmer or on a farm in irrigation work which meets the requirement of performance as an incident to or in conjunction with the primary farming operations of such farmer or such farm, as previously explained, are considered as employed in agriculture under section 3(f) and may qualify for the minimum wage and overtime exemption under section 13(a)(6) or for the overtime exemption provided agricultural workers under section 13(b)(12). Where they are not so employed, they are not considered as agricultural workers (Farmers Reservoir Co. v. McComb, supra), but may qualify for the overtime exemption under section 13(b)(12) relating to irrigation work if their duties and the irrigation system on which they work come within the express language of the statute. Where this is the case, it is not material whether the employees are employed in agriculture.