California Code, Fish and Game Code - FGC § 5943

(a) The owner of a dam shall accord to the public for the purpose of fishing, the right of access to the waters impounded by the dam during the open season for the taking of fish in the stream or river, subject to the regulations of the commission.

(b) Subdivision (a) does not apply to any impoundment of water by a dam that is wholly located on privately owned land that is primarily agricultural or residential in nature if the impounded waters are from a stream or river that is not naturally frequented by fish and if the dam does not prevent the free passage of fish over or around the dam. The Legislature finds and declares that this subdivision is intended to be declaratory of existing law.