California water law is complex, governed by both state and federal law, part property law and part environmental law. Adding to this complexity is the existence of a large number of federal, state and local agencies which play a role in the allocation and management of the state’s water resources.

At the 2019 California Water Law Symposium, Professor Dave Owen from UC Hastings gave the following overview presentation of California water rights, including types of water rights, governing agencies, and sources of regulatory authority, as well as a brief overview of the 2014 Sustainable Groundwater Management Act.

Dave Owen began with a precipitation map of California, noting that the precipitation occurs primarily in the north and in the mountains; significant parts of California are very dry and all of California is quite dry in the summer months.  Those precipitation patterns are reflected in the state’s river systems; there are rivers and surface waterways over most of the state, but most of the flow is concentrated in the Sacramento River valley and on the Northwest Coast.

One of the challenges that creates for California water is that the population centers are primarily in the southern part of the state and along the coast, and one central challenge of California water law and California engineering has been figuring out how to facilitate the movement of water from the places where it naturally occurs to state’s major population centers.  The primary use of water is for agriculture, which faces similar challenges because the primary agricultural regions of the state are relatively dry.

In order to deal with this hydrology, the state has built massive amounts of infrastructure designed to move water around the state from places where it naturally occurs to places where it is needed.  The map on the slide is just a partial showing of the different water infrastructure systems that have been built.

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