Idaho Code § 50-1806
To defray the expense of conveying, controlling, distributing and apportioning such irrigation water as herein provided, the city may assess and apportion the cost thereof against the several water user [users] or landowners using the same, according to the length of time each user or landowner may use such water, and collect such money and keep it in a separate fund to be known as the "Irrigation Fund" of such city for the purpose of paying such expense, including the assessment of the canal or irrigation companies who furnish such city with water for upkeep and maintenance thereof, upon the assigned stock held by such city, provided, that such city may pay said expense out of the general fund and provide for such payment through the general levy, if a majority of the city council so determine.
Idaho Code § 50-1806