Introduction
You are about to enter the IRS Streamlined Program to clean up several years of missed federal Form 1040 returns and FBARs since moving to London six years ago. Your specialist has the federal package well in hand. Then someone mentions that the California Franchise Tax Board has been sending letters to your former San Francisco address asking why you stopped filing California state returns in 2019 — and you realize that the federal Streamlined Procedures do not cover the state tax side at all. State tax compliance for departed US citizens is the single most commonly missed dimension of UK expat tax cleanup, and the consequences of ignoring it can run alongside the federal exposure rather than being absorbed by Streamlined acceptance.
This guide is written for Americans living in England, Scotland, Wales, or Northern Ireland who are entering or considering the Streamlined Filing Compliance Procedures and want to understand the state tax dimension before submission. By the end, you will know which states pursue departed residents most aggressively, what the typical state catch-up looks like, and how state work runs alongside the federal Streamlined package. For our broader Streamlined service overview, see our Streamlined Filing service page.
What Is the IRS Streamlined Program (Definition and Overview)
The IRS Streamlined Program refers to the IRS Streamlined Filing Compliance Procedures introduced in 2012 and substantially expanded in 2014. The official IRS page sits at https://www.irs.gov/individuals/international-taxpayers/streamlined-filing-compliance-procedures. For Americans living in the UK, the relevant track is the Streamlined Foreign Offshore Procedures (SFOP), which covers three years of late or amended Form 1040 plus six years of late FBAR via FinCEN Form 114 plus all required federal information returns (Form 8938, Form 8621, Form 3520, Form 5471, Form 8833) with all federal penalties waived for qualifying non-willful filers.
The Streamlined Procedures operate exclusively at the federal level. US state tax returns — California Form 540, New York Form IT-201 or IT-203, Virginia Form 760, New Mexico Form PIT-1, Massachusetts Form 1, and so on — sit outside the federal Streamlined framework entirely. Each state operates its own tax system through its Department of Revenue or Franchise Tax Board, with its own rules on domicile, residency, source income, filing thresholds, and amnesty programs.
This matters specifically in 2026 because some US states pursue departed residents far more aggressively than the IRS does — particularly California through the Franchise Tax Board at https://www.ftb.ca.gov, New York State through the Department of Taxation and Finance, Virginia through the Department of Taxation, and New Mexico through the Taxation and Revenue Department. These four states use a domicile-based residency framework that treats US citizens as continuing state tax residents until they affirmatively establish domicile in another state or country, which can keep state tax obligations in effect for years after physical departure to the UK.
Who Qualifies — US Expats in the UK Explained
The federal Streamlined Foreign Offshore Procedures apply to US citizens, Green Card holders, dual US-UK citizens, and Accidental Americans living in the UK who meet three conditions: physical presence outside the United States for at least 330 full days in at least one of the three most recent tax years for which the return due date has passed, non-willful past non-compliance, and a properly drafted Form 14653 non-willfulness certification. Almost every long-term UK-resident American meets all three federal conditions. The IRS publication on US citizens and resident aliens abroad sits at https://www.irs.gov/publications/p54.
State residency rules are completely separate and operate under each state's domestic tax law rather than under federal Streamlined eligibility. Common UK-specific misconceptions worth clearing up immediately:
Federal Streamlined acceptance does not cover state tax obligations. A taxpayer can have a clean federal Streamlined acceptance and still face an examination by the California Franchise Tax Board for the same years.
The 330-day non-US residency test for federal Streamlined has no equivalent under state domicile rules. California, New York, Virginia, and New Mexico use intent-based domicile tests rather than physical presence tests.
UK Self Assessment compliance through HMRC does not affect US state tax obligations. State tax sits entirely outside both the UK and US tax systems.
Long-term UK residence does not automatically end state tax residency under aggressive state domicile rules. The departed taxpayer must actively establish that the UK has become their permanent home (domicile) for state purposes, not merely that they are physically living in the UK.
How the Federal Streamlined Program Interacts With US State Tax Returns
States that pursue departed residents aggressively
California, New York, Virginia, New Mexico, and, to a lesser extent, South Carolina maintain domicile-based residency frameworks that can extend state tax obligations for years after physical departure from the state. California Franchise Tax Board (FTB) at https://www.ftb.ca.gov is the most aggressive — California treats a taxpayer as a continuing California domiciliary until evidence is provided that California is no longer the permanent home. The FTB pursues California-source income, including former California salary, California-sourced consulting income, and California real estate sales, well after physical departure.
New York State applies the "permanent place of abode" test — keeping a New York residence available even while living in the UK can trigger continuing New York State residency for tax purposes. Virginia and New Mexico use domicile presumption rules that treat US citizens as continuing state tax residents until they affirmatively establish foreign domicile.
States that recognize departure cleanly
Most US states recognize physical departure from the United States as ending state tax residency. Texas, Florida, Nevada, South Dakota, Washington, Wyoming, Tennessee, New Hampshire, and Alaska have no state income tax, so the question never arises. Most other states — Illinois, Massachusetts, New Jersey, Pennsylvania, Ohio, Michigan, Georgia, North Carolina, Colorado, and similar — accept physical departure plus reasonable evidence of foreign domicile (UK address, UK employment, UK bank accounts, UK life set-up) as terminating state tax residency.
State catch-up returns running alongside the federal Streamlined
Where state tax obligations have been missed alongside federal Form 1040, the state catch-up runs as a parallel workstream to the federal Streamlined package. Most departed-resident state catch-up situations involve three to six years of missed state returns, depending on the state statute of limitations and the period of physical departure. Each state operates its own filing system, amnesty programs (where available), and penalty regime.
Step-by-Step: How US Expats in the UK Handle State Tax Inside a Streamlined Engagement
The first step is the state residency review for each state where you previously filed or held domicile indicators. The specialist documents your last state of residency before UK departure, the date of physical departure, any continuing US ties (US property, US bank accounts, US driver's license, US voter registration, US mailing address), and the state's specific domicile rules.
The second step is to determine the state filing requirement for each catch-up year. For California departed residents, the specialist tests whether California domicile was affirmatively terminated and whether any California-source income continued (former California salary, California real estate, California-sourced consulting). The Multistate Tax Commission's overview of state residency rules is available at https://www.mtc.gov.
The third step is the state catch-up return preparation alongside the federal Streamlined package. Most departed-resident state catch-up situations involve three to six years of state returns — California Form 540NR for non-resident filing or Form 540 for departing-year final filing, New York Form IT-203 for non-resident filing or Form IT-201 for departing-year final filing, Virginia Form 760PY for part-year resident filing, New Mexico Form PIT-1 for residency determination, and Massachusetts Form 1-NR/PY for non-resident filing.
The fourth step is the state amnesty or voluntary disclosure program review, where the state offers one. California Franchise Tax Board offers a Voluntary Disclosure Program for out-of-state taxpayers with California-source income exposure. New York State offers a Voluntary Disclosure and Compliance Program. Several other states offer informal voluntary disclosure routes. ThS Publication 54 c, covering US citizens abroad c, provides the general framework and is available at https://www.irs.gov/publications/p54.
The fifth step is the state final-year return, marking the formal end of state tax residency. California Form 540, marked "Final Return," with an attached statement documenting the termination of California domicile, establishes a clean break point. New York Form IT-201 marked "Final," with attached IT-203-A documents, for permanent move-out from New York State. The clean break establishes that no further state returns are due going forward.
The sixth step is the integrated submission timing across federal and state. The Federal Streamlined package is submitted to the IRS Streamlined processing center in Austin, Texas, via USPS Tracked Delivery; state catch-up returns are submitted separately to each state's Department of Revenue or Franchise Tax Board through the state's standard filing channels. The two workstreams run in parallel but do not interact directly.
The seventh step is the post-submission monitoring for both federal and state. Federal Streamlined acceptance is confirmed through the IRS Account Transcript pulled at the twenty-four-week mark. State catch-up processing varies by state — California FTB typically responds within 6 to 12 weeks, and the New York State Department of Taxation and Finance within 4 to 8 weeks.
The Streamlined Filing Compliance Procedures — What UK Expats Need to Know
The Streamlined Foreign Offshore Procedures (SFOP) cover three years of Form 1040 and six years of FBAR, with all federal penalties waived for qualifying non-willful filers who were physically outside the US for 330 days in at least one of the covered years. The Streamlined Domestic Offshore Procedures (SDOP) apply to U.S.-based U.S. persons who do not meet the foreign residence test and carry a 5 percent Title 26 miscellaneous offshore penalty on the highest aggregate balance of unreported foreign accounts.
For Americans living in the UK, the SFOP track is almost always the relevant federal route. The non-willfulness certification on Form 14653 must honestly explain the taxpayer's specific UK history, and the narrative may mention parallel state catch-up work as part of the overall good-faith compliance effort. The official IRS Streamlined Procedures page is at https://www.irs.gov/compliance/streamlined-filing-compliance-procedures.
TaxYork handles federal Streamlined submissions and coordinates state catch-up work through partner state tax specialists on a fixed-fee basis. For our service overview, see our Streamlined Filing service page.
Real UK Expat Scenario — IRS Streamlined Program Plus California State Catch-Up in Practice
Case Study: A US-Citizen Software Engineer Cleared Federal and California State Together
Patrick is a US citizen aged 38, working as a senior software engineer at a London-based fintech firm on a £125,000 salary plus a £30,000 annual bonus. He moved from San Francisco to London in mid-2019 to take his current role. From 2019 onwards, he had filed no US Form 1040, no California Form 540 or 540NR, and no FBAR — he had assumed that physically leaving the United States ended all US tax obligations, including the California state side. He had retained a Charles Schwab brokerage account from his California years, worth $185,000 and generating approximately $4,800 in annual US dividend income; a Vanguard Roth IRA worth $42,000; and a Fidelity US 401(k) worth $158,000 from his pre-London San Francisco employer. He had also kept a California driver's license active until 2022 (he was unaware that this could indicate continuing California domicile), and his US mailing address remained his parents' San Francisco home, where his California Franchise Tax Board correspondence had been sent.
In late 2025, his father in San Francisco called to tell him that the California Franchise Tax Board had sent a Demand for Tax Return notice asking why no California Form 540 had been filed for 2019 onwards. Patrick engaged TaxYork in November 2025 after a Google search.
The cross-border review identified five immediate exposure points.
First, the federal Form 1040 side qualified for the IRS Streamlined Foreign Offshore Procedures. Patrick met the 330-day non-US residency test in 2022, 2023, and 2024 (no US visits in any of those years), the non-willfulness conditions were met, and no IRS contact had been made on the federal side. The California FTB demand notice was a state matter and did not foreclose federal Streamlined eligibility.
Second, the California state side required a separate catch-up. Patrick's California domicile termination evidence was reviewed — physical departure date of mid-2019, London employment from August 2019, London tenancy from September 2019, HSBC UK current account opened in October 2019, UK Self Assessment first filed for the 2019-20 UK tax year. The retained California driver's license until 2022 and the continued US mailing address at his parents' San Francisco home were domicile indicators on the California side. Still, they did not override the substantive domicile termination evidence.
Third, FBAR was missing for 2019, 2020, 2021, 2022, 2023, and 2024 — six years of FinCEN Form 114 filings to prepare alongside the federal Streamlined package.
Fourth, Form 8938 FATCA was applicable for 2023 and 2024, where Patrick's combined UK account balances exceeded the $300,000-filer thresholds.
Fifth, the Charles Schwab brokerage and the Vanguard Roth IRA continued to generate US-source income that needed to be reported on federal Streamlined Form 1040 returns and, potentially, on California Form 540NR (non-resident) for any years in which California claimed continuing California-source income exposure.
The remediation route ran two parallel workstreams. The federal Streamlined Foreign Offshore Procedures package covered three years of Form 1040 (2022, 2023, 2024) with Form 1116 Foreign Tax Credit absorbing all US federal tax on Patrick's UK salary (UK higher-rate tax of approximately £36,000 per year exceeded equivalent US tax), Schedule B reporting the Charles Schwab US dividend income with FTC absorbing US tax, Form 8938 FATCA attached to the 2023 and 2024 returns, Form 8833 supporting Article 17 election on his London workplace pension, and a Form 14653 non-willfulness narrative explaining the move and the genuine ignorance of continuing federal obligations. Six years of FBARs (2019, 2020, 2021, 2022, 2023, 2024) were filed electronically via the FinCEN BSA E-Filing system marked under the Streamlined Procedures.
The California state workstream ran in parallel. A California Form 540 for tax year 2019, marked "Final Return," with an attached statement documenting the August 2019 departure to London, established the formal termination point of the California domicile. California Form 540NR (non-resident filing) for tax years 2020 through 2024 reported residual California-source income (Charles Schwab dividends sourced to Patrick's then-California broker location), which, on review, proved minimal once Schwab confirmed the account had been re-coded to international upon Patrick's London address update in 2020. Total California state tax exposure across the five years of state returns amounted to approximately $480 in residual California-source income tax, plus interest and late-filing penalties.
A California Franchise Tax Board Voluntary Disclosure Program application was filed alongside the state catch-up returns, securing a waiver of the California late-filing penalties (the Voluntary Disclosure Program waives most penalties for taxpayers coming forward proactively before audit).
The federal Streamlined package was submitted in February 2026 and accepted through silent acceptance in mid-August 2026. The California state package was submitted in late January 2026 and accepted by the California FTB in March 2026, with the Voluntary Disclosure Program penalty waiver granted.
The outcome was full federal IRS compliance under the Streamlined Foreign Offshore Procedures with zero federal penalties (against potential federal exposure of approximately £125,000 in combined FBAR, Form 8938, and Form 1040 penalties), full California state compliance with the Voluntary Disclosure Program penalty waiver (against potential California late-filing penalties of approximately $3,200 plus interest), a defensible Article 17 position on the London workplace pension going forward, and a clean ongoing baseline with annual Form 1040, FBAR, Form 8938, and Form 8833 maintenance under TaxYork engagement. Total TaxYork plus California state specialist fee: approximately £5,800 for the integrated federal Streamlined, plus California state catch-up, plus first-year ongoing engagement, against avoided exposure of approximately £128,000.
Penalties for Non-Compliance — What UK-Based Americans Risk
Federal FBAR non-willful penalties at approximately $16,000 per form per year (inflation-adjusted), Form 8938 missed-filing penalties at $10,000 initial rising to $50,000, Form 1040 failure-to-file penalties at 5 percent per month up to 25 percent of unpaid tax, and Form 8621 missed PFIC filings keeping the tax year open indefinitely under IRC Section 6501(c)(8). The IRS penalty overview sits at https://www.irs.gov/payments/penalty-relief.
State penalties run separately. California Franchise Tax Board failure-to-file penalty is 5 percent per month up to 25 percent of the unpaid California state tax, plus a $135 minimum penalty for late filing of any California return where tax is owed, plus interest at the California adjusted annual rate. New York State's failure-to-file penalty is similarly 5 percent per month up to 25 percent of the unpaid New York State tax. Virginia and New Mexico apply similar percentage-based penalty schedules. State voluntary disclosure programs typically waive most penalties for taxpayers who come forward voluntarily before an audit.
The federal IRS Streamlined Procedures waive every federal penalty for qualifying non-willful filers, but do not affect state penalties. State catch-up returns filed under state voluntary disclosure programs can secure separate state penalty waivers. For our service approach, see our Streamlined Filing service page.
Common Mistakes Americans in the UK Make With State Tax Inside Streamlined
The first mistake is assuming that federal Streamlined acceptance covers state tax obligations. The Streamlined Procedures operate exclusively at the federal level and do not affect state tax compliance, state penalties, or state examination processes.
The second mistake is ignoring correspondence from the California Franchise Tax Board sent to a former California address. The FTB aggressively pursues departed residents, and unresponded notices escalate to liens, levies, and California State Board of Equalization collection actions regardless of the taxpayer's UK location.
The third mistake is failing to file a state "Final Return," which marks the formal end of state tax residency. Without the explicit final-return mark and supporting evidence of domicile termination, states like California can continue to claim the taxpayer as a continuing domiciliary indefinitely.
The fourth mistake is maintaining US ties that indicate continued state domicile — a US driver's license, US voter registration, a US mailing address at a parent's home, a retained US storage unit, a US gym membership, retained US property — without affirmative evidence of foreign domicile establishment. These indicators feed into state domicile examinations on a totality-of-circumstances basis.
The fifth mistake is failing to report California-source income obligations on California Form 540NR after departure. Former California salary trailing into the year of departure, California rental income on retained California property, California-sourced consulting fees, California real estate sales, and California-source stock option exercises all continue to be subject to California state tax on Form 540NR regardless of physical departure.
The sixth mistake is failing to apply for state voluntary disclosure programs where available. California FTB, the New York State Department of Taxation and Finance, and several other states offer voluntary disclosure programs that waive most state penalties for taxpayers who come forward proactively before an audit.
The US-UK Tax Treaty — How It Affects State Tax for Streamlined Filers
The US-UK Income Tax Convention (1975, as amended) operates exclusively at the federal level in the US and does not bind US states. The full treaty text sits on the US Treasury website at https://home.treasury.gov/policy-issues/tax-policy/international-tax. The Article 1(4) Saving Clause preserves the US federal right to tax US citizens regardless of UK residence; state tax sits entirely outside the treaty framework.
For state tax purposes, the treaty Foreign Tax Credit relief available under Article 24 does not flow through to state returns. California, New York, Virginia, and most other states allow their own state-level foreign tax credit only against state-source income that has been taxed by the foreign country, which is a much narrower concept than the federal FTC. For UK-resident filers with continuing California-source income (former California salary trailing into the departure year, California real estate income), the California state tax on that income is generally not relieved by UK tax paid through PAYE or Self Assessment.
The treaty also does not affect state domicile rules. California's domicile test, New York's permanent place of abode test, Virginia's domicile presumption, and New Mexico's domicile rule all operate under state domestic law without reference to the US-UK treaty. A taxpayer can be a UK tax resident under the UK Statutory Residence Test, a treaty resident of the UK under Article 4 of the US-UK Income Tax Convention, and still be a continuing California domiciliary for California state tax purposes.
How TaxYork Helps Americans in the UK With Streamlined and State Tax
TaxYork is a UK-based US expat tax specialist firm serving Americans in England, Scotland, Wales, and Northern Ireland. Our team holds US IRS Enrolled Agent and CPA credentials with deep specialism in the Streamlined Filing Compliance Procedures, federal FBAR via FinCEN Form 114, Form 8938 FATCA, Form 8621 PFIC analysis, the US-UK Income Tax Convention, and end-to-end management of the federal Streamlined timeline. For state tax catch-up work, we coordinate with partner US state tax specialists who hold California, New York, Virginia, New Mexico, and other state credentials as needed for each engagement.
For UK-resident Americans with both federal and state catch-up needs, we deliver the federal Streamlined Foreign Offshore Procedures package end-to-end, alongside parallel state catch-up workstreams covering state residency review, state final-return preparation, state voluntary disclosure program applications (where available), state domicile termination documentation, and post-submission monitoring on both federal and state sides. You can read our broader guidance on our news page.
Contact TaxYork today at info@taxyork.com or visit https://www.taxyork.com/services/ — we help Americans in the UK get fully IRS-compliant federally and state-side, often with all federal penalties eliminated through the Streamlined Procedures and most state penalties eliminated through state voluntary disclosure programs.
Conclusion
Three takeaways matter most for Americans living in the UK, considering the IRS Streamlined Program alongside state tax catch-up in 2026. First, the federal Streamlined Procedures cover federal Form 1040, FBAR, Form 8938, Form 8621, and other federal information returns with all federal penalties waived for qualifying non-willful filers — but the program does not affect state tax obligations, which operate under separate state Department of Revenue or Franchise Tax Board frameworks. Second, California, New York, Virginia, and New Mexico, in particular, aggressively pursue departing residents under domicile-based residency rules, and unresolved state tax obligations can continue to accrue for years after physical departure to the UK, regardless of federal compliance status. Third, state voluntary disclosure programs — California FTB Voluntary Disclosure Program, New York State Voluntary Disclosure and Compliance Program, and similar programs in other states — typically waive most state penalties for taxpayers coming forward proactively before audit, and the state catch-up workstream runs in parallel with the federal Streamlined package rather than waiting for federal acceptance. Speak to a TaxYork adviser today by emailing info@taxyork.com or visiting https://www.taxyork.com/services/.