The SALT deduction cap, explained

SALT stands for state and local taxes — the income (or sales) taxes and property taxes you pay to state and local governments. For decades you could deduct all of them on your federal return if you itemized. The 2017 Tax Cuts and Jobs Act slapped a $10,000 ceiling on that deduction, and it instantly became one of the most fought-over lines in the code. Understanding it comes down to three questions: what counts, whether you itemize at all, and what the current-year cap is.

What SALT actually includes

• State and local income taxes withheld from your paychecks and paid via estimates — OR, if you choose, state and local general sales taxes (useful in no-income-tax states).
• Property taxes on your home and other real estate you own personally.
• Personal property taxes, like the value-based portion of some states' vehicle registration fees.
• You pick income OR sales tax to deduct, not both, then add property taxes — all subject to the single combined cap.

The cap, and why it stings in high-tax states

Before 2018, a New Jersey or California household routinely deducted $25,000-40,000 of combined income and property taxes. The $10,000 cap meant a family paying $18,000 of state income tax and $12,000 of property tax — $30,000 total — could deduct just $10,000, losing the federal benefit on $20,000. That single change is a big reason the share of filers who itemize fell from about 30% to around 10%, since for many the capped SALT plus mortgage interest no longer beat the newly-doubled standard deduction.

SALT only matters if you itemize

This is the part people miss. The SALT deduction is an itemized deduction, so it does nothing unless your total itemized deductions — SALT plus mortgage interest, charitable gifts, and large medical costs — exceed your standard deduction. A renter in a low-tax state with $4,000 of SALT and no mortgage will take the standard deduction and never touch the SALT rules at all. The households for whom SALT is a live issue are homeowners with mortgages in higher-tax states, which is exactly the group the cap was designed to reach.

The workarounds worth knowing

• The sales-tax election: in a no-income-tax state, deduct general sales taxes instead — the IRS provides an optional table, and big purchases like a car or boat can be added on top.
• Pass-through entity (PTET) taxes: most states now let owners of S-corps and partnerships pay state tax at the business level, sidestepping the individual cap entirely — a genuine strategy for business owners, and one worth a CPA's time.
• Prepaying or bunching property tax where allowed, to concentrate deductions into an itemizing year (see the bunching strategy in the standard-vs-itemized article).
• Don't over-engineer it: for a wage earner near the cap, there's rarely a legal workaround, and chasing one usually isn't worth the effort.

The bottom line

SALT is the deduction for the taxes you already pay to your state and city — income (or sales) plus property — but it only counts if you itemize, and it's been capped since 2018. The number and its high-income phase-down have moved with recent legislation, so verify the current-year figure rather than trusting a remembered $10,000. For most renters and standard-deduction filers it's irrelevant; for mortgaged homeowners in high-tax states it's often the whole reason to itemize. Business owners facing the cap should ask a CPA about their state's pass-through entity tax — the one workaround that reliably moves real money.