Unemp. Ins. Code, § 13020

(a) (1) Every employer who pays wages to a resident employee for services performed either within or without this state, or to a nonresident employee for services performed in this state, shall deduct and withhold from those wages, except as provided in subdivision (c) and Sections 13025 and 13026, for each payroll period, a tax computed in that manner as to produce, so far as practicable, with due regard to the credits for personal exemptions allowable under Section 17054 of the Revenue and Taxation Code, a sum which is substantially equivalent to the amount of tax reasonably estimated to be due under Part 10 (commencing with Section 17001) of Division 2 of the Revenue and Taxation Code resulting from the inclusion in the gross income of the employee of the wages which were subject to withholding. The method of determining the amount to be withheld shall be prescribed by the Franchise Tax Board pursuant to Section 18663 of the Revenue and Taxation Code.

(2) For each payroll period ending on or after November 1, 2009, the sum shall comport with the changes made to Section 18663 of the Revenue and Taxation Code, by the act adding this paragraph.

(b) The department upon request may permit the use of accounting machines to calculate the proper amount to be deducted and withheld from wages, if the calculation produces an amount substantially equivalent to the amount of tax required to be withheld under subdivision (a).

(c) Withholding shall not be required by this section with respect to wages, salaries, fees, or other compensation paid by a corporation for services performed in California for that corporation to a nonresident corporate director for director services, including attendance at a board of directors’ meeting.