If you've spent time in tax circles, you've heard versions of this question: I'm leaving California -- or New York -- for good. Which one is going to fight me harder?
It's not a paranoid question. Both states have dedicated audit units staffed by people whose entire job is finding former residents who claim they left but didn't really leave -- or who left in body but not in the way that counts legally. Both states have won large, well-publicized cases. Both states audit people years after they filed their last resident return.
The honest answer is that California and New York are both genuinely aggressive, they're aggressive in different ways, and understanding the difference matters for how you document your departure and what you do in the first two years after you leave.
California: The "You Never Really Left" State
California's Franchise Tax Board is famous for its tenacity. The FTB doesn't just check whether you filed a nonresident return. It evaluates whether you actually changed your domicile -- your permanent home, the place you intend to return to -- and whether California can still reach some of your income even if you technically moved.
The FTB's audit process for former residents focuses on domicile more than raw day counts. California's standard for determining where you're domiciled involves examining the totality of your life: where your spouse and children live, where your social ties are, where you go when you're sick, where your religious community is, where you keep your most cherished possessions. They will look at your credit card records, your cell phone location data, your loyalty program statements, your pets' veterinary records. This is not a figure of speech.
That said, California also has a safe harbor rule: if you spend fewer than 546 days in California over any consecutive two-year period following your move, the FTB cannot assert that you remained a California domiciliary based on time alone. 546 days in two years is an average of 273 days per year, which is a high bar -- meaning many people who think they've "left" are well above it in the early years after relocating.
California also taxes part-year residents on California-source income regardless of domicile. If you sell a California property, receive income from a California business, or exercise stock options that vested while you lived in California, the FTB can reach that income even after you've established domicile elsewhere. Leaving California is not the same as stopping California tax obligations entirely.
What tends to trigger a California residency audit: a large increase in reported income in your last year as a resident (the FTB looks for capital gains or equity events timed around a departure), filing a part-year return after years of full-year resident returns, maintaining property in California, having a spouse or family members who remain in California, or continued involvement in California-based business operations.
New York: The "You Still Have an Apartment There" State
New York takes a structurally different approach, and it catches people who think they've solved the California problem.
New York has a two-prong statutory residency test that operates entirely independently of domicile. You are a New York statutory resident -- and subject to New York income tax on all your income, not just New York-source income -- if you meet both of these conditions:
- You maintain a "permanent place of abode" in New York for substantially all of the tax year.
- You spend more than 183 days in New York during that year.
"Permanent place of abode" has been interpreted broadly by New York courts. It doesn't need to be a home you own. It doesn't even need to be a place where you actually sleep much. Courts have found that a small studio apartment maintained for a family member, or a pied-à-terre used primarily for convenience, qualifies as a permanent place of abode. If you moved to Florida but kept your Manhattan apartment, you may still be a New York statutory resident if you spent more than 183 days in the state that year.
The 183-day count for New York also operates differently than California's domicile analysis. Any part of a day spent in New York State counts as a full day. A morning meeting, a doctor's appointment, a school event -- if you were physically in New York at any point, it's a New York day. New York City maintains its own residency rules on top of the state rules, and City residents face a combined state and city marginal rate that can exceed 13%.
What tends to trigger a New York residency audit: continued property ownership in New York, large income events like a business sale or major capital gains, having a New York-based employer (New York's "convenience of the employer" doctrine has historically taxed remote workers whose employer is in New York, though enforcement has evolved), or inconsistency between your claimed domicile and your actual presence pattern as reconstructed from financial records.
The Key Difference
California is primarily a domicile state. To escape California taxation, you need to establish that your life's center of gravity genuinely moved -- not just your mailing address. California will reconstruct your social and family connections, not just count your days.
New York is primarily a presence and property state. Even if your domicile is unambiguously elsewhere, if you kept your New York apartment and spent more than 183 days there, New York will tax you as a resident. You can have every intention of being a Florida resident and still owe New York taxes because you flew back for 100 business meetings and kept a one-bedroom on the Upper West Side.
This means the departure checklist is different for each state.
For California: sever the ties. Close local accounts. Move your safe deposit box. Transfer your voter registration. Change your car registration. Have your estate planning documents reflect your new state. The more California connections you maintain, the more the FTB can argue you never really left.
For New York: get rid of the apartment, or count your days with precision. If you insist on keeping a New York property, you need to track every day you're physically in New York State -- and stay well under 183. There is no safe harbor rule. There is no totality-of-circumstances escape if you're above 183 days with a place of abode. You just lose.
Which State Wins the Aggression Contest?
Calling it a tie would be diplomatic but slightly dishonest.
California wins on the scope of investigation. The FTB will dig into your life in ways that feel invasive, reconstruct your whereabouts from third-party data, and pursue cases involving comparatively modest amounts of tax. The California audit process is longer, more document-intensive, and harder to win on the merits once the FTB has decided you're a target.
New York wins on the mechanical trap. The statutory resident rules don't require bad intent or ambiguous facts. Keep your apartment, exceed 183 days, and New York wins automatically -- no matter how clearly your domicile is elsewhere. It's simpler and, in many cases, more immediately expensive.
If you're a high-income individual moving from either state, the honest advice is the same: treat both seriously, document everything, and don't make decisions based on what you've heard worked for someone else. State tax law is jurisdiction-specific, fact-specific, and the consequences of getting it wrong are proportional to your income level.
What "Good Documentation" Actually Means
Both California and New York will ask for the same categories of evidence: your physical location on each day of the year in question, supporting documentation for your claimed domicile (lease, utility bills, community ties), and records showing when you were in the audit state versus elsewhere.
"I kept a calendar" is not compelling. Neither are credit card records alone, which show where you spent money but not where you slept. The most defensible position combines:
- A verified, day-by-day location record corroborated by multiple independent sources
- Supporting documents organized by date and location (boarding passes, hotel receipts, lease agreements)
- A clear narrative that explains your domicile change and the steps you took to establish it
Residency audits, when they happen, happen years later. The records you're building today are the records you'll be defending with in 2027 or 2028.
Don't reconstruct. Document in real time. Start your free 7-day trial at ResidencyProof. Build the verified day-by-day timeline that holds up when California or New York comes looking -- and know exactly where you stand before you file.