Groundwater, for example, is virtually unregulated. Under Texas law, groundwater belongs to the person who owns the land above it or to the person who can capture it. It is private property that may be used or sold without receiving prior authority from the state.
Laws governing surface water in Texas are much more complicated and vary according to location.
Surface water rights are a recognized property right and can be sold. Generally, water rights are not leased but sold. If the entire amount of water is not used in a given year, sales of surplus water are permitted but only among similar users. Surplus water from an irrigation right cannot be sold to municipalities for domestic consumption, for example. A key issue when considering water sales is the question of ownership.