Cal. WAT § 1005.4

(a) Cessation of or reduction in the extraction of ground water, to permit the replenishment of such ground water by the use of water from an alternate nontributary source, is hereby declared to be a reasonable beneficial use of the ground water to the extent and in the amount that water from such alternate source is applied to beneficial use, not exceeding, however, the amount of such reduction. No lapse, reduction or loss of any right in ground water, shall occur under such conditions.

(b) Any such user of water from an alternative source may file with the board, on or before December 31st of each calendar year, a statement of the amount of reduction in the extraction of groundwater as a result of water from the alternative source having been so applied to reasonable beneficial use during the next preceding water year (October 1st to September 30th) to permit replenishment of such groundwater. However, failure to file such a statement shall in no way affect the right of a user to claim the benefit of this section.

(c) The provisions of this section apply only as to the cessation of, or reduction in, the extraction of ground water within that area in this state defined by the exterior boundaries of every county, except the Counties of San Luis Obispo, Santa Barbara, Ventura, Los Angeles, Orange, San Diego, Imperial, Riverside, and San Bernardino.

(d) The term “nontributary source,” as used in this section, shall be deemed to include water imported from another watershed or water conserved and saved in the watershed by a water conservation plan or works without which such water of the same watershed would have wasted, or would not have reached the underground source of supply of the owner relying upon this section.