Maryland HSA Tax Rules: Why the County Tax Can't Diverge From the State
Maryland has a mandatory local income tax on top of the state tax -- all 23 counties and Baltimore City levy one, with no opting out. That sounds like it could create the same kind of question Ohio's ~600 municipalities did. It doesn't, and the reason is structural, not just a matching policy choice.
Key takeaways
- Maryland conforms to federal HSA tax treatment -- contributions through payroll or a cafeteria plan are excluded from Maryland taxable income.
- All 23 Maryland counties plus Baltimore City levy a mandatory "piggyback" tax, but it's calculated as a percentage of the already-adjusted state figure, not an independently determined tax base.
- That structural difference is why Maryland's county tax can't diverge from the state's HSA treatment the way Ohio's municipalities or New York City's separate tax base can.
State level: conforms
Maryland follows federal HSA rules: contributions made through payroll or a cafeteria plan are excluded from Maryland taxable income, and qualifying withdrawals are tax-free at the state level. This part is the same as most conforming states.
Why the county "piggyback" tax can't diverge
Every Maryland county and Baltimore City levies its own local income tax, commonly called the "piggyback" tax -- a holdover term from the fiscal arrangement that created it. Rates run from about 2.25% in Allegany County up to 3.2% in Montgomery County, Prince George's County, Howard County, and Baltimore City, and there's no opting out. Here's the structural detail that matters for HSA purposes: the piggyback tax is calculated as a percentage applied to the same Maryland taxable income already used to compute the state tax -- it isn't a separately determined tax base the way each Ohio municipality's is, or the way New York City's is. Since the HSA exclusion has already been applied by the time Maryland taxable income is calculated, the county tax is mathematically derived from a figure that already reflects it. There's no separate step where a county could tax something the state doesn't.
One practical detail: residence, not workplace
The piggyback rate that applies to you is based on your county of residence, not where your job is physically located. Someone living in Howard County but commuting to work in Anne Arundel County still pays the Howard County rate. This doesn't change anything about HSA treatment -- it's simply a detail worth knowing if you're trying to figure out which specific rate applies to your paycheck.
Sources: Maryland Comptroller's Office, county income tax rate schedules; IRS Publication 969 for federal HSA treatment.