I agree in a philosophical sense, but in a U.S. legal sense, water rights are often treated as property, though it depends on precisely when they were granted and with what terms, and why/how they're being abrogated. The U.S.'s "takings clause" jurisprudence has a fairly expansive definition of what constitutes "property", and water rights disputes often end up tangled up in it. If a river literally runs out of water then a farmer probably has no claim, but if the state reallocates its water (to balance with other uses, for environmental reasons, to build up a reserve, etc.) then it ends up in court.