I made this assumption myself early on and nearly watched a neighbor lose everything because of it. When you buy irrigated land in a prior appropriation state, the water right may be appurtenant to the land—but that does not mean the transfer is automatic or clean. Decrees get separated from parcels through sloppy estate splits, old quit-claim deeds, or irrigation district paperwork that nobody updated for thirty years. I've seen buyers close on beautiful hay ground and discover the adjudicated right stayed with a different parcel because someone filed wrong in 1987.
Before you close on anything with irrigation history, pull the actual water court decree, verify the point of diversion, and confirm the right is currently attached to the parcel you're buying—not assumed to be attached. Your title company is not equipped to catch this. A water attorney or your state engineer's office is.
Has anyone here actually had a clean title report on irrigated land that still had a severed water right hiding underneath it?