ORS § 540.240
In the case of a partnership ditch, pipeline or reservoir, or a ditch, pipeline or reservoir owned in common or by a mutual irrigation company incorporated under the laws of this state, the wages of the assistant watermaster and expenses incurred by the assistant in making the distribution provided for by ORS 540.210 to 540.240, and the necessary and proper expense of installation and maintenance of measuring devices and headgates to provide for the just distribution of water among the several users in accordance with their respective and relative rights, shall be a lien upon the ditch, pipeline or reservoir. The lien shall attach to each tract of land entitled to the use of water for irrigation from the ditch, pipeline or reservoir, and upon the crops produced upon the lands during the irrigation season for which the distribution is made. If a ditch, pipeline or reservoir is owned or operated by a person engaged in the business of selling or renting water from the ditch, pipeline or reservoir, the wages and expense shall be a lien upon the ditch, pipeline or reservoir. The wages and expense shall be paid monthly by the water users, the mutual irrigation company, or the person engaged in the business of selling or renting water from a ditch, pipeline or reservoir.
ORS 540.240