In California, water rights involve the right to use water, not the right to own water. While the Water Code implies the existence of groundwater rights, their doctrinal bases and characteristics are essentially the product of the decisions of the courts. There is no comprehensive law in California that determines the right to groundwater. If disputes arise, the courts decide priorities in individual cases considering types of water rights and judicial decisions that have set precedent.
Types of Groundwater Rights
- Overlying Rights - All property owners above a common aquifer possess a mutual right to the reasonable and beneficial use of a groundwater resource on land overlying the aquifer from which the water is taken. Overlying rights are correlative (related to each other) and overlying users of a common water source must share the resource on a pro rata basis in times of shortage. A proper overlying use takes precedence over all non-overlying uses.
- Appropriative Rights - Non-overlying uses and public uses, such as municipal uses, are called appropriative uses. Among groundwater appropriators the "first in time, first in right" priority system applies. Appropriative users are entitled to use the surplus water available after the overlying user's rights are satisfied.
- Prescriptive Rights - Prescriptive rights are gained by trespass or unauthorized taking that can yield a title because it was allowed to continue longer than the five year statute of limitations. Prescriptive rights can only be obtained against private entities. Claim of a prescriptive water right to non-surplus water by an appropriator must be supported by many specific conditions which include a showing that the pumping was actual, open and notorious, hostile, adverse to the overlying user, continuous and uninterrupted for five years, and under a claim of right.
Other Types of Water Rights
- Pueblo Right - A water right possessed by a municipality which, as a successor of a Spanish or Mexican pueblo, is entitled to the beneficial use of all needed, naturally-occurring surface and groundwater of the original pueblo watershed. Water use under a pueblo right must occur within the modern city limits, and excess water may not be sold outside the city.
- Riparian - Pertaining to the bank of a river, or any area where water naturally touches land. Riparian Rights are a matter of land ownership. To possess a riparian right it is necessary to own property which physically touches a river, stream, pond, lake or well-defined underground channel. Riparian rights refer to surface water, not groundwater. Riparian rights are lost if the land is severed from the water source so it is no longer contiguous.