Cal. RTC § 17054.5

(a) (1) There shall be allowed as a credit against the “net tax” (as defined in Section 17039) of a qualified individual an amount equal to 30 percent of the net tax.

(2) For taxable years beginning on or after January 1, 1987, and before January 1, 1988, a qualified individual means a qualified joint custody head of household as defined in subdivision (c).

(3) For taxable years beginning on or after January 1, 1988, a qualified individual means either of the following:

(A) A “qualified joint custody head of household” as defined in subdivision (c).

(B) A “qualified taxpayer” as defined in subdivision (e).

(4) The amount of the credit under this section shall not exceed two hundred dollars ($200) for any taxable year.

(b) For each taxable year beginning on or after January 1, 1988, the Franchise Tax Board shall recompute the maximum credit prescribed in subdivision (a). That computation shall be made as follows:

(1) The California Department of Industrial Relations shall transmit annually to the Franchise Tax Board the percentage change in the California Consumer Price Index as modified for rental equivalent homeownership for all items from June of the prior calendar year to June of the current calendar year, no later than August 1 of the current calendar year.

(2) The Franchise Tax Board shall add 100 percent to the percentage change figure which is furnished to them pursuant to paragraph (1) and divide the result by 100.

(3) The Franchise Tax Board shall multiply the immediately preceding taxable year credit by the inflation adjustment factor determined in paragraph (2), and round off the resulting product to the nearest one dollar ($1).

(c) “Qualified joint custody head of household” means an individual who meets all of the following:

(1) Is not married at the close of the taxable year, or files a separate return and does not have his or her spouse as a member of his or her household during the entire taxable year.

(2) Maintains as his or her home a household which constitutes for the taxable year the principal place of abode for a qualifying child, as defined in subdivision (d), for no less than 146 days of the taxable year but no more than 219 days of the taxable year, under a decree of dissolution or separate maintenance, or under a written agreement between the parents prior to the issuance of a decree of dissolution or separate maintenance where the proceedings have been initiated.

(3) Furnishes over one-half the cost of maintaining the household during the taxable year.

(4) Does not qualify as a head of household under Section 17042 or as a surviving spouse under Section 17046.

(d) For purposes of this section, a “qualifying child” means a son, stepson, daughter, or stepdaughter of the taxpayer or a descendant of a son or daughter of the taxpayer, but if that son, stepson, daughter, stepdaughter, or descendant is married at the close of the taxpayer’s taxable year, only if the taxpayer is entitled to a credit for the taxable year for that person under Section 17054.

(e) “Qualified taxpayer” means an individual who meets all of the following:

(1) Is married and files a separate return.

(2) During the last six months of the taxable year the taxpayer’s spouse was not a member of the taxpayer’s household.

(3) Maintains a household, whether or not the taxpayer’s home, which constitutes the principal place of abode of a dependent mother or father of the taxpayer for the taxable year.

(4) Furnishes over one-half of the cost of maintaining the household during the taxable year.

(5) Does not qualify as a head of household under Section 17042 or as a surviving spouse under Section 17046.