FTB Pub 1032:
The nonmilitary spouse of a military servicemember who is domiciled in California, but leaves the state with the
military spouse on PCS orders outside California, becomes a nonresident upon leaving California. The MSRRA does
not alter this result. All income received or earned while a California resident is subject to tax. While a nonresident,
only income from California sources is subject to tax.
So, since the Military Spouse Residency Relief Act allows the spouse to elect the same state of residency as the servicemember, while in CA she is a CA resident who, like the servicemember, becomes a CA nonresident while residing with her husband in SC.
No CA return.Also, the MSRRA as adopted by SC in SC Revenue Ruling #10-5:
income from services performed by a
spouse of a servicemember is not taxable to the state where the services are performed if the
spouse is a nonresident who is in the state solely to be with the servicemember serving in
compliance with military orders. Prior to this Act, regardless of the state of domicile, the spouse,
like any other worker, would be taxed on wages and other service income in South Carolina if
the income was earned in South Carolina.
Additionally, the Veteran's Benefits and Transitions Act of 2018 allows the spouse to claim the servicemember's state of residency even if she has never stepped foot in the state.
Bottom line? Do not file a CA return. File a SC return as a nonresident to get a refund of tax paid on spouse's wages. Neither the servicemember nor his spouse will pay state taxes on their W-2 wage income.
Retired, no salvage value.