Reassessment impact

When reassessments happen

Reassessment is the periodic update of a property's assessed value to reflect current market conditions or changes to the property itself. Each state — and often each county — runs on its own schedule. Roughly:

• Annual reassessment states (TX, FL, GA, NV, parts of NY): every parcel gets a new value every year, usually mailed in spring or summer
• Biennial / triennial states (MA, OH, IL Cook County triennial cycle): every 2–3 years
• Longer cycles (PA, NC, parts of NY, parts of WV): 4–8 years between full reassessments, with interim "trends" sometimes applied
• Trigger-based states (CA via Prop 13, MI via Headlee, FL Save Our Homes): values track at a capped rate until a triggering event (sale, major construction)

What triggers a reassessment

• Scheduled cycle — most common, mailed annually or per cycle
• Sale of the property — in trigger-based states, the new owner gets a fresh assessment, often a sharp jump
• Permitted construction — additions, renovations over a threshold, new pools or outbuildings
• Subdivision or merger — splitting one parcel into two, or combining adjacent parcels
• Appeal or correction — your own appeal, or a correction the assessor catches
• Catastrophic damage — wildfire, hurricane, flood — usually triggers a downward reassessment

Annual tax change = (New AV − Old AV) × (Mill rate ÷ 1,000)

Reading your reassessment notice

Every reassessment notice will contain four numbers worth understanding:

• Prior assessed value — what you were assessed at last cycle
• New assessed value — what you're being assessed at now
• Estimated tax impact — sometimes provided, sometimes not. If it's missing, this calculator gives you the number.
• Appeal deadline — usually 30–60 days from the notice date. This is the single most important date on the page.

Caps that suppress reassessment

Several states cap how much assessed value can rise year-over-year, even when market values are climbing fast:

• California (Prop 13): assessed value can rise no more than 2% per year, until a sale or new construction
• Florida (Save Our Homes): assessed value on a homestead can rise no more than 3% per year or CPI, whichever is lower
• Texas: homestead assessed value capped at +10% per year
• Michigan (Headlee / Proposal A): taxable value capped at +5% or CPI, whichever is lower, until a sale
• Oregon (Measure 50): taxable value can rise no more than 3% per year

In capped states, a sale resets the cap to current market — which is why new buyers often pay dramatically more property tax than long-time neighbors with similar homes.

Worked examples

Example 1 — Routine reassessment increase. Assessed value jumps from $325,000 to $395,000 in a 18.5 mill jurisdiction:

• Old annual tax: $325,000 × 0.0185 = $6,013
• New annual tax: $395,000 × 0.0185 = $7,308
• Annual increase: $1,295 (+21.5%)
• Monthly escrow bump: ~$108

Example 2 — Trigger event in California. Long-time owner sells a home assessed at $385,000 (built up under Prop 13's 2% cap). The new buyer pays $1,100,000. The assessment resets:

• New buyer's first-year assessed value: $1,100,000
• At a 1.10% effective rate (typical CA): annual tax ~$12,100
• Long-time owner's annual tax was ~$4,235
• Same house, $7,865/year more for the new buyer — and that gap will widen as long as they hold

Example 3 — Renovation reassessment. Adding a $80,000 finished basement and bathroom in a 22 mill jurisdiction:

• Marginal assessed value added: ~$60,000 (assessors typically apply 70–90% of permit cost)
• Marginal annual tax: $60,000 × 0.022 = $1,320
• Cumulative over a 20-year hold: ~$26,400, even before growth
• Worth it? Often yes — but factor it into the renovation budget upfront

Common mistakes

• Ignoring the notice. The reassessment notice starts the appeal clock. Skim it the day it arrives, even if you think it's fine.
• Assuming the reassessment is correct. Mass reassessments are run by software. Errors are common — wrong sqft, wrong condition rating, wrong neighborhood code. Pull your property record card and verify.
• Comparing to your home's previous value, not market. Reassessments target market value (or a fraction of it). The right comparison is "is the new assessed value reasonable given recent sales?", not "did it go up a lot from last year?".
• Waiting to file. Most appeal windows are 30–60 days. Filing in week 1 or week 2 gives you time to gather evidence, request informal review, and prepare for a hearing. Filing on day 59 leaves you cornered.
• Confusing assessed value change with tax change. A 20% jump in assessed value doesn't always mean a 20% jump in tax — mill rates can be lowered to offset (some states require it when reassessments are revenue-neutral).

Frequently asked questions

How often does my county reassess?

Check your county assessor's website — every county publishes its reassessment cycle. Annual is most common; 2–3 year cycles are typical in the Northeast and Midwest; longer cycles (5+ years) exist in some rural areas.

Can I refuse to let the assessor on my property?

Generally yes, but the assessor will then estimate based on whatever they can see from the road and from records. That estimate is usually higher than what they'd find inside, so refusing access often hurts you. Cooperation usually pays.

Why didn't the mill rate go down when assessed values went up?

Some states require revenue-neutral millage adjustments after mass reassessments (Michigan, Pennsylvania); others don't, leaving bills to rise with values. Check your state's truth-in-taxation rules.

If I appeal, when do the savings start?

Usually the current tax year — the appeal applies to the new assessment that triggered it. If you've already paid the bill, the savings come back as a refund or as a credit on the next bill.

Do small renovations trigger reassessment?

Cosmetic interior updates (kitchen refresh, painting, flooring) generally don't trigger reassessment because they don't pull permits and don't change footprint. Anything requiring a permit — additions, structural changes, major systems — usually does.

What is "equalization" and how does it affect reassessment?

Equalization is a state-level multiplier applied to county assessments to bring all counties to a consistent ratio of market value. It's most commonly seen in states like Illinois, where the "equalized assessed value" is your local AV times a state factor. A reassessment plus an equalization change can compound.

What's the difference between assessed value, taxable value, and market value?

Market value: what the home would sell for. Assessed value: what the county records on file as the basis for tax. Taxable value: assessed value minus exemptions, multiplied by any equalization factor. The mill rate is applied to the taxable value, not the assessed value.

Should I appeal even a small increase?

If the new assessed value looks higher than what your home would currently sell for, yes. Even small successful reductions compound across multiple years, and a one-hour informal review can yield surprisingly large wins if there's a record-card error.