Moving from California to South Carolina: Residency, Taxes, and What to Prove

In California

California is both a major origin state, since many nurses domiciled here take travel contracts elsewhere, and the single highest-paying destination state for travel assignments. A nurse's tax home must be a genuine, regularly-returned-to residence with duplicated living expenses; nurses who claim a tax home in Texas or Florida but never actually go back risk having the FTB or IRS reclassify housing stipends as taxable wages if the facts show California, not the claimed state, is really home. A nurse domiciled outside California who works a temporary California assignment as a W-2 traveler does not become a California resident from that assignment alone, but the wages earned during the California contract are still California-source and must be reported on a nonresident Form 540NR.

In South Carolina

South Carolina's large hospital systems (MUSC in Charleston, Prisma Health, McLeod) make it a significant travel-nurse assignment market. Because South Carolina has no day-count residency trigger, a nurse working consecutive South Carolina contracts is not automatically pulled into residency the way they would be in a 183-day state; the exposure runs through South Carolina's domicile test instead, meaning a nurse who buys a home, registers to vote, or otherwise shows intent to make South Carolina permanent can become domiciled regardless of the nominal 'tax home' claimed elsewhere.

In California

California is the most aggressive jock-tax state. FTB counts not just game days but practices, walkthroughs, and even voluntary workouts held at a California team facility during game week, which can turn one road game into three or four California duty days. With the Lakers, Clippers, Warriors, Kings, 49ers, Rams, Chargers, Dodgers, Giants, Padres, and Athletics all based here, nonresident athletes playing any California team face California nonresident tax on their duty-day-apportioned income, while California-domiciled athletes owe California tax on their full worldwide income.

In South Carolina

Charleston and Greenville host minor-league and college sports rather than a major-league franchise, so South Carolina's jock-tax exposure is almost entirely on the visiting-player side: nonresident athletes on teams playing in South Carolina owe apportioned South Carolina tax on the personal-service income allocated to South Carolina duty days, following the state's general rule taxing nonresidents on South Carolina-source personal service income.

In California

The nine-month presumption under §17016 only creates a rebuttable presumption of residency past that point; it does not create a safe harbor below it. Spending fewer than nine months in California does not guarantee nonresidency; FTB still applies the closest-connections test. This is the classic dual-home audit target described across Bogleheads and r/tax threads: a retiree who keeps the California house, splits time with a Nevada or Arizona property, but leaves a spouse, kids, doctors, or the majority of actual annual days in California.

In South Carolina

Because South Carolina runs no day-count test, a snowbird can spend an extended winter in South Carolina without becoming a resident, as long as they do not develop the intent to make South Carolina their permanent home; the Department's own guidance states a nonresident spending winter months in South Carolina does not automatically become a South Carolina resident. The risk flips for someone who buys a South Carolina home, joins clubs, opens local bank accounts, and gradually shifts their center of life there, as in Brown, where the taxpayer was found domiciled in South Carolina despite lacking a South Carolina driver's license or vehicle registration that year.

In California

California has no convenience-of-employer rule like New York's. A nonresident who physically performs all their work outside California for a California-headquartered employer is not California-taxed on those wages solely because the employer is based here. The trigger is the employee's own residency and physical work location, not the employer's address. A California resident, however, owes California tax on remote wages regardless of where the employer sits.

In South Carolina

South Carolina has no convenience-of-the-employer rule. A remote worker physically performing work from South Carolina owes South Carolina tax on that personal service income (since South Carolina taxes residents' personal service income regardless of source and nonresidents' South Carolina-source personal service income), and the credit for taxes paid to other states (Code § 12-6-3400) is the mechanism for avoiding double taxation if the employer's home state also asserts a claim.

In California

California follows the federal Servicemembers Civil Relief Act and the Military Spouses Residency Relief Act. Active-duty military domiciled outside California but stationed here under orders are not California residents and their military pay isn't California-taxed. Under MSRRA and the Veterans Benefits and Transition Act, a nonmilitary spouse can elect the servicemember's domicile for state tax purposes instead of being pulled into California residency by physical presence alone.

In South Carolina

South Carolina follows the federal Servicemembers Civil Relief Act, the Military Spouses Residency Relief Act, and the Veterans Benefits and Transition Act: a servicemember does not lose or acquire South Carolina domicile solely by being present or absent under military orders, and a spouse may elect to use the servicemember's state of residence for tax purposes regardless of when the marriage occurred. Under S.C. Regulation 117-640.2, a servicemember who entered service while domiciled in South Carolina is presumed to remain a South Carolina resident for tax purposes unless they affirmatively establish a new domicile and abandon South Carolina, even if the new state (like Texas or Florida) has no income tax.

In California

Federal law (49 U.S.C. §40116) limits taxation of air carrier employees to their state of residence and any state where they earn more than 50% of their pay, overriding ordinary duty-day sourcing. California hosts major crew bases at LAX and SFO, so this carve-out matters heavily for California-based flight crew who fly national or international routes.

In South Carolina

Charlotte Douglas (just across the North Carolina line) and smaller in-state airports mean some airline crew live in South Carolina while based elsewhere. Federal law (49 U.S.C. § 40116) limits state taxation of air carrier employees to their state of residence and, narrowly, a state where more than 50% of pay is earned; crew domiciled in South Carolina are taxed on personal service income under the state's standard resident rules.