Introduction A US citizen who moves from San Francisco to London assumes that federal Form 1040 is the only US filing that follows them across the Atlantic. Five years later, the California Franchise Tax Board sends a Notice of Proposed Assessment for $42,000 of state income tax, plus interest, on the basis that the California […]
A US citizen who moves from San Francisco to London assumes that federal Form 1040 is the only US filing that follows them across the Atlantic. Five years later, the California Franchise Tax Board sends a Notice of Proposed Assessment for $42,000 of state income tax, plus interest, on the basis that the California domicile was never properly broken. This is the trap state tax obligations US expats face under UK rules, and it catches more American expats every year than almost any other US-side issue. State tax is the silent compliance gap that persists after the move, while everyone is focused on federal returns.
This guide is written for US citizens and Green Card holders living in the United Kingdom — recent UK arrivals from California, New York, Virginia, and other “sticky” states; long-term UK residents with continuing US ties; and dual US-UK citizens. By the end, you will know which states keep claiming you after you leave, how to break domicile cleanly, and what ongoing state filings genuinely apply during UK residence. For broader context, see our service page at https://www.jungletax.co.uk/services/.
State tax obligations for US expats, UK rules refer to the US state-level income tax filing and payment requirements that continue to apply to US citizens and Green Card holders after they relocate to the United Kingdom. Unlike the US federal tax, which applies on a citizenship basis to every US person regardless of residence, the US state tax applies on a residence- and domicile-based basis. The key distinction is between the 43 states that impose an individual income tax and the 7 states with no income tax (Alaska, Florida, Nevada, South Dakota, Tennessee, Texas, Washington, and Wyoming, plus New Hampshire, which taxes only interest and dividends).
The framework matters because some US states — notably California, New York, Virginia, New Mexico, and South Carolina — continue to assert aggressive domicile claims long after a person physically leaves. The official IRS overview of US citizens abroad sits at https://www.irs.gov/individuals/international-taxpayers/us-citizens-and-resident-aliens-abroad. Domicile is a common-law concept built on physical presence, intent to return, family ties, property ownership, voter registration, driving license, and bank accounts. Without active steps to break domicile, the original state continues to assert taxing rights on worldwide income.
This matters in 2026 because state tax enforcement against departing residents has significantly increased, particularly from California’s Franchise Tax Board. UK-based Americans who left California or New York without properly breaking state domicile are now receiving assessment notices five to ten years after departure, with interest accruing throughout.
Three drivers make state tax compliance urgent in 2026.
First, state revenue authorities are using federal data feeds more aggressively. Federal Form 1040 filed with a UK address triggers automatic flags at certain state tax authorities, particularly the California Franchise Tax Board and the New York State Department of Taxation and Finance. Both authorities now systematically pursue former residents who continue to file federal returns without filing or formally breaking state residency.
Second, the gap between US state tax paid and the UK Foreign Tax Credit available on Form 1116 has narrowed. State income tax is generally creditable against UK tax under the US-UK treaty’s saving clause and HMRC’s foreign tax relief rules. Still, the interaction is fact-specific and depends on whether the state tax represents income that the UK would otherwise tax. HMRC’s foreign tax relief overview sits at https://www.gov.uk/tax-foreign-income/taxed-twice.
Third, the new UK Foreign Income and Gains regime, which replaced non-dom rules from 6 April 2025, affects how US-source income (including income attributable to a US state) is treated in the UK for new arrivals. HMRC’s FIG guidance is available at https://www.gov.uk/government/publications/changes-to-the-taxation-of-non-uk-domiciled-individuals. Year-one positioning under FIG interacts with state tax exit planning. For wider context see our news page at https://www.jungletax.co.uk/jungle-tax-news-updates/.
California uses a residence test under Section 17014 of the California Revenue and Taxation Code that defines a resident as either present in California for other than a temporary or transitory purpose, or domiciled in California and outside California for a temporary or transitory purpose. The California Franchise Tax Board guidance is available at https://www.ftb.ca.gov. Former California residents who move to the UK can remain California residents under the second limb, provided they can prove their move is permanent. The Franchise Tax Board considers factors such as UK home ownership versus rental, UK family ties, return-to-California visits, retained California property, retained California driving license, retained California voter registration, and retained California bank accounts.
California Form 540NR is filed by part-year and nonresidents with California-source income. Even a former resident who has cleanly broken domicile may need to continue filing Form 540NR if they retain California rental property, California-source business income, or California-source partnership distributions.
New York operates two parallel tests. The domicile test resembles California’s and applies to people whose true and permanent home remains New York. The statutory residence test under New York Tax Law Section 605(b)(1)(B) deems a person resident for tax purposes if they maintain a permanent place of abode in New York and spend 183 days or more in New York during the year. Even a non-domiciled UK resident who keeps a New York apartment and visits enough days can trip the statutory test.
The New York State Department of Taxation and Finance guidance sits at https://www.tax.ny.gov. Breaking New York residency requires giving up a permanent place of abode in New York, formally changing domicile, and limiting the New York day-count to fewer than 183 days. New York City imposes a separate local income tax on residents but generally not on nonresidents, so cleanly breaking New York City residence has an additional benefit.
Virginia operates an aggressive domicile rule that can keep a former resident on the hook indefinitely without specific exit steps. Virginia Department of Taxation guidance considers driver’s license, voter registration, vehicle registration, and family location as primary indicators. New Mexico and South Carolina apply similar common-law domicile tests with shorter histories than California but increasingly active enforcement.
Most other states with income tax — Illinois, Massachusetts, Pennsylvania, Ohio, Michigan, Georgia, and others — apply residence-based tests that release a person cleanly on physical departure, provided the basic exit steps are taken (filing a final part-year return, removing voter registration, surrendering a driving license). The IRS publication on US citizens abroad covering federal interactions sits at https://www.irs.gov/publications/p54.
The first step is the pre-move audit. Document every state tie — property ownership or rental, driving license, voter registration, vehicle registration, bank accounts, professional licenses, club memberships, family location, employment ties, and physical presence days for the prior three to five years.
The second step is the timing decision. Most states recognize a change of domicile only with affirmative steps, and the cleanest break is to complete those steps before or simultaneously with the move to the UK rather than after the fact. A move at the start of a US tax year (1 January) simplifies the final part-year state return.
The third step is the affirmative exit checklist. Surrender the US state driving license and obtain a UK provisional or full driving license. Remove voter registration in the former state (US federal voting rights are preserved separately under the Uniformed and Overseas Citizens Absentee Voting Act). Close or convert state bank accounts where practical. Sell or formally lease out US property and break statutory presence ties.
The fourth step is the documentation file. Maintain UK tenancy agreements, UK utility bills, UK Council Tax records, UK driving license, UK bank account opening documents, UK Self Assessment confirmation, and UK Statutory Residence Test evidence. The HMRC SRT overview sits at https://www.gov.uk/government/publications/rdr3-statutory-residence-test-srt.
The fifth step is the final part-year state return. File the final state return as a part-year resident for the year of departure, paying state tax on income earned during the residence portion of the year and indicating “moved abroad” with the new UK address. California Form 540NR is used for part-year California residents and includes Schedule CA (540NR) for adjustments.
The sixth step is ongoing nonresident filings. Continued state-source income (US rental property, US partnership distributions, retained US business income) may trigger ongoing nonresident state returns even after domicile is broken. State nonresident returns are typically required only where state-source income arises.
Alex is a US citizen, aged thirty-five, who lived and worked in San Francisco for nine years before relocating to London in March 2023 for a senior engineering role with a UK technology company at a £165,000 salary. He kept his California driving license (intending to renew it on his next US visit), retained his Chase account opened at a San Francisco branch, did not remove his California voter registration, and kept a single-family rental property in Oakland that generated $48,000 in annual gross rental income. His federal Form 1040 was filed each year through a generic US preparer with a UK address.
In late 2025, almost three years after departure, Alex received a California Franchise Tax Board Notice of Proposed Assessment for the 2023 and 2024 tax years, totaling approximately $54,000 of California state tax plus interest. The Franchise Tax Board’s position was that Alex had not affirmatively broken California domicile — the driving license renewal, voter registration, and California bank account were each cited as ties demonstrating continuing California domicile under Section 17014.
Jungle Tax was engaged in early 2026. The remediation route had two limbs. First, we filed a Statement of Domicile Change with the Franchise Tax Board, supported by extensive UK documentation — UK tenancy, UK Council Tax, UK driving license (issued in late 2025 after we identified the issue), UK Self Assessment filings, UK bank statements, UK Statutory Residence Test confirmation as UK tax resident, UK NHS GP registration, and UK NI number registration. Second, we filed amended California Form 540NR returns for 2023 and 2024 as part-year residents (for the period before March 2023) and nonresidents thereafter, reporting only California rental property income and pre-departure wage income.
The negotiated outcome with the Franchise Tax Board was a reduction of the proposed assessment from $54,000 to approximately $9,200, reflecting tax due only on the California-source rental property income and pre-departure California-resident wages. Going forward, Alex files California Form 540NR each year to report only his California rental income, and his federal Form 1040 continues with Form 1116, the Foreign Tax Credit, fully offsetting US federal tax on his UK salary. The Oakland property was placed on the market for sale in early 2026 to eliminate the ongoing California nexus.
The first mistake is assuming that a federal Form 1040 filing with a UK address automatically breaks state domicile. It does not. State domicile requires affirmative state-specific steps documented contemporaneously with the move.
The second mistake is keeping a US state driving license “just for convenience” during US visits. State driving licenses are primary domicile indicators in California, Virginia, and several other sticky states. Surrendering and obtaining a UK license is one of the cleanest single signals of changed domicile.
The third mistake is leaving voter registration in the former state. Voting in a state election after moving abroad is sometimes treated by state tax authorities as conclusive evidence of continued domicile. Federal voting rights are preserved separately under federal law via the Federal Voting Assistance Program at https://www.fvap.gov.
The fourth mistake is retaining a US permanent place of abode in a state that is sticky. New York’s statutory residence test is triggered by a permanent place of abode plus 183 days. A retained New York apartment plus regular US visits can keep a UK resident on New York’s books indefinitely.
The fifth mistake is failing to file the final part-year state return. Skipping the part-year return after a mid-year move can be treated by some states as evidence of continued full-year residency by default. Filing the final return with the “moved abroad” indication is a clear sign of exit.
The sixth mistake is forgetting to file nonresident state returns for retained US-source income. A UK-resident American with a Texas rental property has no Texas filing obligation (Texas has no income tax), but the same person with a California rental property continues to file California Form 540NR annually on the rental income.
Jungle Tax is a UK firm of Chartered Tax Advisers specializing in US-UK cross-border taxation. Our team holds combined UK CIOT and ATT qualifications alongside US IRS Enrolled Agent and CPA credentials, which means a single engagement covers federal Form 1040, state tax returns for California, New York, Virginia, and other sticky states, UK Self Assessment, and HMRC residency planning. State tax planning is built into every US-citizen UK resident engagement we run, not as a separate workstream.
For US-citizen UK residents we handle pre-departure state tax planning, final part-year state returns, ongoing nonresident state filings for US-source income, state domicile audit defence with Franchise Tax Board and other state authorities, IRS Streamlined Foreign Offshore Procedures for federal catch-up combined with state tax cleanup, and ongoing coordination of state tax paid as Foreign Tax Credit on UK Self Assessment under HMRC foreign tax relief rules.
For a free initial cross-border assessment contact us at info@jungletax.co.uk or visit https://www.jungletax.co.uk. You can also read related guidance on our news page at https://www.jungletax.co.uk/jungle-tax-news-updates/.
Three takeaways matter most for any US citizen moving to or already living in the UK in 2026. First, state tax obligations for US expats and UK rules survive the move to the UK and operate independently of federal Form 1040 — state domicile must be broken with affirmative documented steps, not by assumption. Second, California, New York, Virginia, New Mexico, and South Carolina are the sticky states whose tax authorities most aggressively pursue former residents, with the California Franchise Tax Board the most active in 2026. Third, ongoing US-source income, such as US rental property, continues to trigger nonresident state returns even after domicile is cleanly broken, and the interaction with the UK Foreign Tax Credit on Form 1116 and HMRC foreign tax relief needs coordinated planning. Speak to a Jungle Tax adviser today by emailing info@jungletax.co.uk or visiting https://www.jungletax.co.uk/services/.
Potentially yes, if the California domicile was not broken with affirmative steps. California Revenue and Taxation Code Section 17014 keeps former residents on the hook unless they can prove the move to the UK is permanent rather than temporary.
Alaska, Florida, Nevada, South Dakota, Tennessee, Texas, Washington, and Wyoming impose no individual income tax. New Hampshire taxes only interest and dividend income (phasing out by 2027). US citizens who last resided in any of these states typically have no continuing US state tax exposure after moving to the UK
New York Tax Law Section 605(b)(1)(B) deems a person resident for tax purposes if they maintain a permanent place of abode in New York and spend 183 days or more in New York during the year. A UK-resident American who keeps a New York apartment and visits enough days can trigger statutory residency regardless of domicile status. Giving up the New York permanent place of abode is the cleanest defense.
Yes, in most cases. HMRC’s foreign tax relief rules treat US state income tax on UK-resident income as creditable against UK tax on the same income, like US federal tax. The mechanics depend on whether both jurisdictions tax the income and the specific category. Coordination is typically straightforward for state tax on US-source wages or rental income.
Yes, usually. Most states require a nonresident return (such as California Form 540NR) reporting state-source income, including rental property, business income, and partnership distributions. The filing applies even after domicile is broken, because the state taxes nonresidents on income sourced within its borders.
Yes. We handle California Franchise Tax Board residency audits and Notices of Proposed Assessment for UK-resident former Californians, preparing the Statement of Domicile Change with UK supporting documentation, negotiating amended California Form 540NR filings, and coordinating outcomes with federal Form 1040 and UK Self Assessment positions. Contact us at info@jungletax.co.uk to start with a free initial assessment.
