A.C.
I can't speak to the specifics of water rights/NM property, since I've never lived there.
However, I will suggest that you contact and have a buyers agent represent you. By law, the realtor has to do their best to help the seller, and they are out to get the best price for the seller. Good realtors will try to balance this, but it is an inherent conflict of interest to have a realtor, whose job it is to try to sell a house for the best price, also try to help you buy a house.... A buyer's agent is a licensed realtor that only represents buys and does not ever list houses for sale. A good buyer's agent in NM should be able to assist you with your questions and concerns and help you find you need to make a decision, and they will only represent you the buyer. We used a buyer's agent for buying our home, and were very happy we did.
Best of luck with your decision.