Cal. Rev. & Tax. Code § 24349

(a) There shall be allowed as a depreciation deduction a reasonable allowance for the exhaustion, wear and tear (including a reasonable allowance for obsolescence)—
1. (1) Of property used in the trade or business; or
2. (2) Of property held for the production of income.
(b) Except as otherwise provided in subdivision (c), for taxable years ending after December 31, 1958, the term “reasonable allowance” as used in subdivision (a) shall include, but shall not be limited to, an allowance computed in accordance with regulations prescribed by the Franchise Tax Board, under any of the following methods:
1. (1) The straight-line method.
2. (2) The declining balance method, using a rate not exceeding twice the rate that would have been used had the annual allowance been computed under the method described in paragraph (1).
3. (3) The sum of the years-digits method.
4. (4) Any other consistent method productive of an annual allowance that, when added to all allowances for the period commencing with the taxpayer’s use of the property and including the taxable year, does not, during the first two-thirds of the useful life of the property, exceed the total of those allowances that would have been used had those allowances been computed under the method described in paragraph (2).
  Nothing in this subdivision shall be construed to limit or reduce an allowance otherwise allowable under subdivision (a).
(c) Any grapevine replaced in a vineyard in California in a taxable year beginning on or after January 1, 1992, as a direct result of a phylloxera infestation in that vineyard, and any grapevine replaced in a vineyard in California in a taxable year beginning on or after January 1, 1997, as a direct result of Pierce’s disease in that vineyard, shall have a useful life of five years, except that it shall have a class life of 10 years for purposes of depreciation under Section 168(g)(2) of the Internal Revenue Code where the taxpayer has made an election under Section 263A(d)(3) of the Internal Revenue Code not to capitalize costs of the infested vineyard. Every taxpayer claiming a deduction under this section with respect to a grapevine as described in this subdivision shall obtain a written certification from an independent state-certified integrated pest management adviser, or a state agricultural commissioner or adviser, that specifies that the replanting was necessary to restore a vineyard infested with phylloxera or Pierce’s disease. The taxpayer shall retain the certification for future audit purposes.
(d) For purposes of this part, the deduction for property leased to governments and other tax-exempt entities, as defined in Section 168(h) of the Internal Revenue Code, shall be limited to the amount determined under Section 168(g) of the Internal Revenue Code, relating to alternative depreciation system for certain property.
(e)
1. (1) In the case of any building erected or improvements made on leased property, if the building or improvement is property to which this section applies, the depreciation deduction shall be determined under the provisions of this section.
2. (2) An improvement shall be treated for purposes of determining gain or loss under this part as disposed of by the lessor when so disposed of or abandoned if both of the following occur:
  1. (A) The improvement is made by the lessor of leased property for the lessee of that property.
  2. (B) The improvement is irrevocably disposed of or abandoned by the lessor at the termination of the lease by the lessee.
    This subdivision shall not apply to any property to which Section 168 of the Internal Revenue Code does not apply for federal purposes by reason of Section 168(f) of the Internal Revenue Code. Any election made under Section 168(f)(1) of the Internal Revenue Code for federal purposes with respect to that property shall be treated as a binding election for state purposes under this subdivision with respect to that same property and no separate election under subdivision (e) of Section 23051.5 with respect to that property shall be allowed.
3. (3)
  1. (A) In determining a lease term, both of the following shall apply:
    1. (i) There shall be taken into account options to renew.
    2. (ii) Two or more successive leases which are part of the same transaction (or a series of related transactions) with respect to the same or substantially similar property shall be treated as one lease.
  2. (B) For purposes of clause (i) of subparagraph (A), in the case of nonresidential real property or residential rental property, there shall not be taken into account any option to renew at fair market value determined at the time of renewal.
(f)
1. (1) Section 167(g) of the Internal Revenue Code, relating to depreciation under income forecast method, shall apply except as otherwise provided.
2. (2) Section 167(g)(2)(C) of the Internal Revenue Code is modified by substituting “Section 19521” in lieu of “Section 460(b)(7)” of the Internal Revenue Code.
3. (3) Section 167(g)(5)(D) of the Internal Revenue Code is modified by substituting “Part 10.2 (commencing with Section 18401) (other than Article 2 (commencing with Section 19021) and Sections 19142 to 19150, inclusive)” in lieu of “Subtitle F (other than Sections 6654 and 6655).”
4. (4) Section 167(g)(5)(E) of the Internal Revenue Code, relating to treatment of distribution costs, shall not apply.
5. (5) Section 167(g)(7) of the Internal Revenue Code, relating to treatment of participations and residuals, shall not apply.