Best Tax-Free Municipal Bond Funds for California and Washington Families in 2026

By Kevin Luu, Co-Founder and Chief Learning Officer. Reviewed on 2026-09-30.

There is no single best tax-free municipal bond fund. The right one depends on your state. For a California household in the top federal bracket, a low-cost California municipal bond fund usually leaves more after tax than a national fund such as Vanguard’s VTEAX, because only a fund with at least half of its assets in California (or U.S. government) obligations passes its interest through free of California tax. For a Washington household, a low-cost national AMT-free fund like VTEAX or the iShares National Muni Bond ETF (MUB) is usually enough, since Washington has no wage or interest income tax in 2026.

This guide is written for two-earner families earning roughly $600,000 to $1.2 million, often with RSUs, who keep a real bond or cash reserve in a taxable brokerage account. It covers how muni funds are taxed, the after-tax math at $900,000 of income in each state, how the common funds differ, and where munis do not belong. It is general education, not a recommendation to buy any fund.

How municipal bond fund income is taxed in 2026

Interest on bonds issued by states, cities and their agencies is generally excluded from federal gross income. When a fund holds those bonds, it pays you “exempt-interest dividends,” which you report on Form 1040 line 2a but do not pay federal income tax on. Four details matter at this income level:

• No 3.8% Net Investment Income Tax. The NIIT applies to married couples with modified AGI over $250,000, which covers every family reading this. Tax-exempt interest is not net investment income (Form 8960 instructions). Taxable bond interest is.
• State tax depends on where the bonds come from. California taxes interest from other states’ bonds. A mutual fund’s exempt-interest dividends are free of California tax only if the fund has at least 50% of its assets in California (or U.S. government) obligations; otherwise the federally exempt dividends are added back to California income (FTB Schedule CA (540) instructions, 2025).
• Private activity bonds can trigger AMT. Interest on “specified private activity bonds” is an AMT preference item (Form 6251 instructions, line 2g). This matters for families exercising ISOs, who are the ones most likely to be in AMT.
• Capital gains are still taxable. If the fund sells bonds at a gain and distributes it, or you sell fund shares at a gain, that gain is taxed like any other. California has no lower rate for capital gains, and Washington’s capital gains tax can apply to large gains on the sale of fund shares.

The after-tax math at $900,000 of household income

Assume a married couple, two kids, $900,000 of W-2 income including RSU vests, and about $860,000 of taxable income. They hold $500,000 in bonds in a taxable brokerage account as their “safe” reserve (for example, earmarked for a home purchase or to offset concentration in employer stock). The yields below are round, hypothetical numbers chosen to show the mechanics, not current quotes.

• Taxable bond fund: 4.5% yield
• National muni fund: 3.2% yield
• California muni fund: 3.0% yield

Marginal rates used. Federal: 37% (the 2026 married filing jointly 37% bracket starts at $768,700 of taxable income, per Rev. Proc. 2025-32). NIIT: 3.8%. California: 10.3% (the 2025 joint schedule applies 10.3% from $742,958 to $891,542; 2026 schedules were not yet published, per FTB). The extra state tax gives no federal deduction, because at this income the 2026 SALT cap phases down to $10,000, which California income tax already uses up.

What the table shows:

• In California, the in-state fund wins by about $650 a year over the national fund and about $4,000 over the taxable fund on this $500,000. Its tax-equivalent yield is 3.0% divided by (1 minus 0.511), or about 6.1%. A taxable bond would need to yield that much to match it.
• In Washington, the national fund wins. A California-only fund gives up yield and diversification for a state tax break a Washington family does not need.
• In both states, the taxable fund loses at these assumptions. That can flip when taxable yields rise relative to muni yields, so compare the current yields yourself before buying, not once and forever.

At $1.2 million of income the case for a California fund gets stronger: California’s marginal rate rises to 11.3% above $891,542 of taxable income, the 1% Behavioral Health Services Tax is added on taxable income over $1,000,000, and the 12.3% bracket starts above $1,485,906 (2025 schedules). At $600,000, federal drops to 35% on the top slice and California to 9.3%, and the gap between the three options narrows.

How the common funds compare

These are the names that come up most often. They are examples of each category, not recommendations, and the fund’s current prospectus is the authority on fees, holdings and risks.

Vanguard Tax-Exempt Bond Index (VTEAX) and its ETF share class (VTEB)

VTEAX seeks to track the S&P National AMT-Free Municipal Bond Index, a broad index of investment-grade munis (Vanguard fund page). It is an index fund with a low expense ratio; check the current prospectus for the exact figure. Because the index is AMT-free, it is relevant for families exercising ISOs. Because it holds bonds from every state, California will tax most or all of its dividends. For Washington families it is a sensible default.

iShares National Muni Bond ETF (MUB)

Similar exposure to VTEB in ETF form: a national, investment-grade, AMT-free index. The choice between MUB and VTEB is mostly about which brokerage you use and small differences in cost and index construction.

California funds: iShares California Muni Bond ETF (CMF) and Vanguard’s California tax-exempt funds

CMF tracks an AMT-free index of investment-grade California municipal bonds (iShares fund page). Vanguard runs California Intermediate-Term (VCADX) and California Long-Term (VCLAX) tax-exempt funds, which are actively managed and aimed at California residents. The trade-off is concentration: all of your bond reserve depends on one state’s issuers.

Short-term muni funds

Short-duration muni funds, such as Vanguard’s short-term tax-exempt ETF (VTES), move less when rates change. They fit money you will spend in the next one to three years, such as a down payment or a tax bill due on RSU vests.

Where municipal bonds do not belong

Munis only make sense in a taxable account. Inside a 401(k), IRA, Roth IRA, mega backdoor Roth or 529, income is already sheltered, so a muni’s lower yield is simply lost. (An HSA is sheltered federally, but California does not recognize HSAs and taxes their interest and earnings in the year earned, per the FTB Schedule CA (540) instructions, 2025.) If you hold bonds in both taxable and retirement accounts, the usual pattern is taxable bonds inside the retirement accounts and munis in the brokerage account.

Kids’ accounts are a closer call. Tax-exempt interest does not count toward the kiddie tax (Form 8615 instructions), which for 2026 taxes a child’s unearned income above $2,700 at the parents’ rate. For a large UTMA account holding bonds, that can matter. For a small one, the first $1,350 of a child’s unearned income is tax-free for 2026 anyway, so a taxable bond fund may do just as well. See our guides to calculating kiddie tax and UTMA withdrawal tax rules.

A five-question check before you pick a fund

1. Which state will you live in for the next few years? For California residents, a California fund is usually the first category to compare. For Washington residents, a national fund usually is. If a move is likely, a national fund avoids selling later.
2. Are you exercising ISOs or otherwise near AMT? If so, AMT-free funds keep private activity bond interest out of your AMT calculation. For 2026 the married AMT exemption of $140,200 phases out starting at $1,000,000 of AMT income.
3. When will you need the money? Under three years: short-term. Longer: intermediate. Long-term funds carry the most rate risk.
4. Is this account taxable? If not, skip munis.
5. What is the current yield gap? Divide the muni yield by (1 minus your combined marginal rate) and compare it to a taxable bond fund of similar quality and duration.

Common mistakes we see

• A California family holding a national muni fund and assuming the income is fully tax-free. It is federally tax-free; California usually taxes it.
• Buying a high-yield muni fund for the yield without noticing the lower credit quality, when the money was meant to be the safe reserve.
• Selling a muni fund at a gain after moving from Washington to California, or the reverse, without checking which state taxes the gain.
• Assuming Washington will stay income-tax-free. Washington has enacted a 9.9% tax on AGI over $1,000,000 starting in 2028 (WA DOR). How it will treat muni interest is not yet defined, so revisit this decision before then.

What to write down for your kids

The fund choice is a small decision. The reasoning behind it is what your children can use later: why the family keeps a reserve at all, why it sits in bonds rather than employer stock, and why the state you live in changed which fund you bought. A short Decision Memo in your FamilyKnowledge® Library, one page with the date, the numbers and the reason, turns a brokerage line item into a lesson. As Kevin Luu, co-founder of Bright Advisers, puts it: “Your kids don’t need to inherit your portfolio. They need to inherit your decision-making process.”

Frequently asked questions

Is VTEAX tax-free in California?

Mostly not. VTEAX’s dividends are free of federal income tax and the NIIT, but the fund holds bonds from across the country and does not keep at least 50% of its assets in California obligations, so California taxes its exempt-interest dividends as ordinary income. Check the fund’s annual tax statement, which shows the share of income by state, when you prepare your return.

Are muni bond ETFs better than muni mutual funds?

For tax purposes they are close. Muni income is the same either way, and bond funds rarely distribute large capital gains. ETFs have no minimums and trade during the day; some mutual fund share classes allow automatic investing. Pick on cost, index and where your accounts are held, not on the wrapper.

Do I pay Washington capital gains tax on muni fund income?

No, interest is not a capital gain. Washington’s 7% capital gains tax (9.9% on gains over $1,000,000) applies to long-term gains on assets such as stocks and fund shares above the annual standard deduction, which was $278,000 for 2025 (WA DOR). A large gain when you sell fund shares could be taxed.

Next step

Pull last year’s 1099-DIV from your brokerage account and look at box 12 (exempt-interest dividends), then find the fund’s year-end tax supplement, which shows the share of income by state. If you live in California and most of that income came from other states, rerun the table above with your own balance and current yields. For how bond holdings fit your overall tax picture, see our tax management and investment risk management pages, or start with a Tax & Wealth Assessment.

This is general education, and the right move depends on your family’s full picture.

Written by

Kevin Luu

Co-Founder and Chief Learning Officer, Bright Advisers

Kevin has advised high-income W-2 tech and biotech families since 2015, and leads the education-first Age Five Family Office from Brea, California.

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