The lien is the mechanism, and it is why a mortgage lender does not trust you with the money. Because the tax is imposed on the property, non-payment attaches to the property. In most jurisdictions the unpaid tax becomes a lien recorded against the parcel and, if it stays unpaid, is enforced by a sale of the parcel or of the lien itself. Whether that lien outranks a mortgage recorded years earlier is a question of state law, and federal law's own treatment of the question is the clearest evidence of how it usually comes out. 26 USC 6323(b)(6) provides that the federal tax lien is subordinate, with respect to real property, to a holder of a lien on that property securing "a tax of general application levied by any taxing authority based upon the value of such property" or a special assessment for a public improvement, but only "if such lien is entitled under local law to priority over security interests in such property which are prior in time." So the United States itself steps behind a local ad valorem tax lien where local law gives that lien priority over earlier interests, and the statute's conditional wording is Congress acknowledging that the answer comes from the state.
The practical corollary is the escrow account. A mortgage lender whose lien can be outranked by an unpaid tax has a direct interest in the tax being paid, which is why servicers collect it monthly and pay it themselves rather than relying on the borrower. Regulation Z goes further on some loans and simply requires it: 12 CFR 1026.35(b)(1) mandates an escrow account, established before consummation, on a higher-priced mortgage loan secured by a first lien on a principal dwelling. The published material on escrow covers how the account works and what limits apply to it.
Naming the unit, because a bill is unreadable without it. Property tax rates are commonly expressed in mills. A mill is one dollar per $1,000 of taxable value, so a rate of 20 mills is 2 percent of taxable value and a rate of 68 mills is 6.8 percent of it. A bill often lists several rates, one for each taxing body whose boundaries include the parcel, and the millage that matters is their total. Because the rate is applied to taxable value rather than to market value, and because taxable value is frequently a fraction of market value, a high-sounding millage can be an ordinary effective rate and the two figures cannot be compared across jurisdictions without both halves.
The chain from a property to a bill runs in one direction and it is worth having in order: market value, then an assessment ratio, giving assessed value, then any exemptions are subtracted, giving taxable value, then the total millage is applied, giving the gross tax, then any credits are subtracted, giving the bill. Each step is set by a different rule and only some of them are challengeable by the owner.
Federal law decides the split when a property is sold, and it does not follow the billing schedule. IRC 164(d)(1) apportions the real property tax for the year of a sale between the parties: the part "properly allocable to that part of such year which ends on the day before the date of the sale" is treated as imposed on the seller, and the part allocable to the portion beginning on the date of sale is treated as imposed on the purchaser. So the dividing line is the day of closing, by days, regardless of which party the local authority actually bills or when the bill falls due. That is the statutory basis of the proration line on a closing statement, and it is also why a buyer can end up paying a bill covering months before they owned the property, or receiving a credit for months after. IRC 164(d)(2)(A) closes the circle for the case where the local rules make neither party liable, providing that "the party holding the property at the time the tax becomes a lien on the property shall be considered liable" for it. The statute reaches for the lien, which is the tax's real point of attachment.
The personal property limb is the part neither guide covers and it is worth money. IRC 164(b)(1) defines the term precisely: "the term 'personal property tax' means an ad valorem tax which is imposed on an annual basis in respect of personal property." Three conditions sit in that sentence and all three have to be met. The charge must be ad valorem, meaning computed on value; it must be imposed on an annual basis; and it must be in respect of personal property. A vehicle registration bill frequently mixes charges that meet the test with charges that do not, so a flat plate fee, a title fee, or a charge based on weight or age rather than value is not a personal property tax however it is labeled, while a line computed as a percentage of the vehicle's value is. Where a single bill combines both, only the qualifying portion is deductible and the bill has to be split.
The federal deduction, and the ceiling it sits under. Both varieties are deductible only as itemized deductions, and only inside the combined limit on state and local taxes, which is $40,400 for 2026 and half that on a separate return. The cap is reduced for higher incomes, by 30 cents for every dollar of modified adjusted gross income above $505,000, though never below a $10,000 floor. Because state and local income or sales taxes compete for the same ceiling, a household in a jurisdiction with an income tax often finds its property tax produces no federal benefit at all. Two limits on the amount catch people. A payment into escrow is not itself deductible: the IRS states that you may not be able to deduct the total you pay into the account and can deduct only the real estate taxes the lender actually paid out of it to the taxing authority. And an itemized charge for services to specific property is not a tax even when it is billed by the taxing authority, so a per-household trash collection charge on a property tax bill is not deductible, which is the real-property counterpart of the plate-fee point above.
