Pursuant to California Family Code section 4058 gross income for purposes of child support "means income from whatever source derived". Subsection (1) specifically identifies social security benefits as included.
While FC section 4058 is a child support statute, there is no companion definition of income for temporary spousal support and as a result section 4058 is generally applied to that context as well.
The question often arises whether Social Security is inputted into the support calculation as a taxable or nontaxable benefit - federal taxes are imposed on some of Social Security benefits, depending upon on combined income (the sum of adjusted gross income plus nontaxable interest plus one-half of Social Security benefits). The bottom line is that ask the Court to include it within "other taxable income" to avoid paying both taxes on the income and higher child or spousal support!
Thurman W. Arnold III