How Does California Tax a CDHP Health Savings Account?

California does not conform to the federal rules for Health Savings Accounts, so the state taxes your HSA contributions and the account’s yearly earnings even though both are tax-free on your federal return. Qualified withdrawals, on the other hand, escape California tax because the money was already taxed on the way in. That mismatch is the core of how California taxes an HSA, and it drives a set of state-only adjustments you have to make every year you hold the account.

The authority is direct. California Revenue and Taxation Code Section 17215.4 says that Internal Revenue Code Section 223, which is the entire federal HSA framework, does not apply for state purposes.¹ Everything below flows from that single non-conformity.

Contributions Are Added Back to California Income

If you deducted your own HSA contributions on your federal return, you have to add that amount back when you calculate California adjusted gross income. Employer contributions are handled the same way. The amount reported in Box 12, Code W of your W-2, which was excluded from your federal wages, has to be reported as additional California income on Schedule CA (540), Line 1h, Column C.²

The practical effect is straightforward. If your employer put $2,000 into your HSA this year, you owe California income tax on that $2,000, even though it never appeared as wages on your federal return. The same is true for any pre-tax payroll contributions you made through a cafeteria plan. California treats the whole amount as taxable wages.

Earnings Inside the Account Are Taxed Every Year

Federally, interest, dividends, and capital gains inside an HSA grow tax-free until you take a non-qualified distribution. California rejects that treatment. Interest and other earnings in your HSA are taxable in the year they are earned, not deferred until withdrawal.²

If you invest your HSA balance in mutual funds or individual securities, the reporting gets more involved. Because California is already taxing contributions and annual earnings, your California cost basis in those investments will not match your federal basis. When you sell holdings inside the HSA, you may need to compute a California-specific gain or loss on Schedule D (540). Most HSA custodians do not track state-level basis, so you have to keep those records yourself. Without accurate basis tracking, you can end up paying California tax twice on the same dollars.

Withdrawals: No California Tax on Qualified Distributions

Because California already taxed the contributions and the annual earnings, it does not tax the money again when you spend it. A distribution used for a qualified medical expense generates no California addition on your return.

Non-qualified distributions are handled through a subtraction. When money you pull for a non-medical purpose is included in your federal income, you subtract it on Schedule CA (540), Line 8f, because the underlying amount was already taxed at the state level.² The federal 20% penalty on non-qualified withdrawals before age 65 is a federal charge; it is not repeated at the California level.

The overall pattern is the mirror image of the federal system. The federal government gives you a deduction going in and penalizes misuse. California taxes you going in and leaves the withdrawals alone. The real cost to residents is the lost upfront deduction plus the annual tax on account earnings, which compounds over the years you hold the account.

The Archer MSA Rollover Trap

Rolling an Archer Medical Savings Account into an HSA is a non-event on your federal return. California treats it as a non-qualified distribution. The rollover amount is included in your California taxable income and is hit with an additional 12.5% penalty tax.² If you have an Archer MSA and a California return, price out that state cost before you move the balance.

What Happens When a California Resident Inherits an HSA

Beneficiary designation matters more for California residents than for HSA holders in conforming states. A spouse who inherits the account simply takes it over. It stays an HSA, and the surviving spouse can keep using it for qualified medical expenses and can keep contributing if they are otherwise eligible.

Anyone other than a spouse gets a much worse result. The HSA loses its tax-advantaged status on the date of death, and the full fair market value becomes taxable income to the beneficiary in the year of death. The beneficiary can reduce that amount by any of the deceased’s qualified medical expenses they pay within one year of the date of death. If the estate is the beneficiary, the value goes on the deceased’s final income tax return.³

The California angle is what makes this especially harsh. Because California never allowed a deduction for the original contributions, a non-spouse beneficiary is effectively taxed on money that California already taxed once at the account holder’s level. Naming a spouse as beneficiary whenever possible sidesteps the outcome.

Records California Filers Have to Keep

Federal record-keeping is limited to proving that each distribution went to a qualified medical expense, that the expense was not reimbursed elsewhere, and that you did not also claim it as an itemized deduction.³

California adds another layer. Because interest, dividends, and gains inside the account are reported on your state return every year, and because your investments carry a California-specific basis, you need to keep:

Every personal contribution and every employer contribution, by year.
Every interest, dividend, and capital gain distribution posted to the account.
Every buy and sell inside the account, with the California basis for each lot.
The running gap between federal basis and California basis on each holding.

This is the only way to avoid paying California tax twice on the same money when you eventually sell an investment or take a distribution.

Federal Rules Still Govern Who Can Contribute and How Much

California’s non-conformity changes how the account is taxed, not who can open one or how much can go in. Federal eligibility, contribution limits, and the definition of a qualified medical expense continue to apply on the federal side. For 2026, the maximum contribution is $4,400 for self-only HDHP coverage and $8,750 for family coverage, with an additional $1,000 catch-up for account holders age 55 and older.⁴³ You can make 2026 contributions any time through April 15, 2027.⁵ Whatever you contribute under those federal rules is what California will add back on your state return.

Pending Conformity Legislation

Bills to align California with the federal HSA rules have been introduced repeatedly, and none has become law. The most recent is Assembly Bill 781, from the 2025–2026 legislative session. It would allow a California income tax deduction for HSA contributions matching the federal deduction, for tax years beginning on or after January 1, 2026, through December 31, 2030.⁶ The Franchise Tax Board estimated the revenue reduction at roughly $70 million per year and, as of the March 2025 bill analysis, had not taken a position. The bill had not been enacted. Until a conformity measure is signed into law, every California adjustment described above stays in place.

1
California Legislative Information. California Revenue and Taxation Code 17215.4
2
Franchise Tax Board. 2025 Instructions for Schedule CA (540)
3
Internal Revenue Service. Publication 969 (2025), Health Savings Accounts and Other Tax-Favored Health Plans
4
IRS. Notice 2026-5 HSA Inflation Adjusted Items
5
Internal Revenue Service. Instructions for Form 8889 (2025)
6
Franchise Tax Board. Bill Analysis, AB 781 Health Savings Account Deduction Conformity