How Connecticut property taxes actually work — mill rate × assessed value (70% of fair market value). Why two homes priced the same can owe wildly different tax bills.
The Connecticut property tax formula
Every Connecticut municipality sets its own mill rate annually. A mill rate is the tax owed per $1,000 of assessed value. The assessment in CT is set at 70% of the property's fair market value as determined by the most recent town-wide revaluation (revaluations happen every five years per state law).
The formula is straightforward: Annual property tax = (Mill rate × Assessed value) ÷ 1,000.
Example: A home with a fair market value of $500,000 has an assessed value of $350,000 (70%). If the town's mill rate is 30, the annual tax is (30 × 350,000) ÷ 1,000 = $10,500.
Why mill rates vary so dramatically
Connecticut has some of the widest mill-rate spreads in the country. A few examples of approximate 2025 mill rates:
- Greenwich: 11.59 — among the lowest in the state
- Salisbury: 11.18
- New Canaan: 14.18
- Darien: 17.99
- Westport: 16.86
- Branford: ~27
- New Haven: ~39
- West Hartford: ~41
- Hartford: 68.95 — among the highest residential rates
- Waterbury: ~60
What the spread actually means
Don't compare mill rates directly without also comparing assessed values. A Greenwich home assessed at $1.4M pays roughly $16,000/year at a 11.59 mill rate. A Hartford home assessed at $200K pays roughly $13,800/year at a 68.95 mill rate. The Hartford homeowner is paying nearly the same total tax on a property worth 1/7 as much.
What changes year-to-year is the mill rate itself. Towns with stable grand lists (total assessed value across the town) tend to keep mill rates flat. Towns with shrinking grand lists or rising budgets — common in older cities — raise mill rates to compensate, which can rapidly compound for homeowners.
How taxes affect buyers and sellers
Buyers should factor estimated annual taxes into their monthly affordability calculation. On a $500K home, the difference between a 12 mill rate and a 40 mill rate is roughly $9,800 per year, or $815/month — meaningful on a mortgage application and in monthly budgeting.
Sellers in high-mill-rate towns sometimes see lower resale prices because savvy buyers price taxes into their offers. Sellers in low-mill-rate towns can often command a small premium.
How to verify a property's tax bill
Don't trust the MLS listing's stated tax bill — it's often outdated. Pull the most recent tax bill directly from the town's assessor or finance department website, and check whether the property has any exemptions (veteran, elderly, disability) that won't transfer to you.