1. Read the assessment, not just the bill
Connecticut taxes real property on 70% of fair market value as of the assessment date, usually October 1 (CGS §12-63). Your tax bill = assessed value × mill rate ÷ 1,000, plus any fire or special district mills. If the mill rate went up but the assessment looks right, an appeal may not help. If the assessment looks high versus recent sales of similar homes, that is the usual issue.
Ask the assessor for your property record card (size, bathrooms, extras, condition). Factual errors are often easier to fix than a pure “value is too high” argument. Town mill rates and a quick estimate are on this site’s town list and calculator.
2. Talk to the assessor first
Many towns will review an obvious data error without a formal hearing. Start with the assessor’s office in the town where the property sits. The state does not run a central appeal desk: assessment and taxation are municipal (CT OPM: statutes governing property assessment).
3. File with the Board of Assessment Appeals
If you still disagree, the first formal step is a written application to the town’s Board of Assessment Appeals (BAA), not the tax collector and not OPM. Under CGS §12-111:
- File in writing (or email if the board allows it) on or before February 20.
- If the assessor received an extension to file the grand list, the deadline moves to March 20 and hearings are typically in April.
- The application usually needs the owner’s name, property description, your estimate of value, a reason, and a signature (owner or authorized agent).
- The board notifies you of a hearing date. Bring comparable sales, an appraisal if you have one, photos, and the property record card.
Under CGS §12-113, the board generally will not reduce an assessment unless you (or your attorney or agent) appear and offer or consent to be sworn and answer questions about the property. Missing the hearing can end the appeal at this level.
Use the town’s own BAA form. There is no single statewide e-file portal. Find the assessor from your town page or the town’s official website.
4. If you lose at the board
You may be able to take the board’s action to the Superior Court for that judicial district. CGS §12-117a describes an application within two months of the mailing of notice of the board’s action. Court practice, bonds, and appraisal rules are beyond this page — that is when most people talk to a Connecticut attorney. A separate statute (CGS §12-119) covers limited cases of alleged illegal assessment; it is not the usual path.
Official sources
- CGS §12-111 — appeals to the Board of Assessment Appeals
- CGS §12-113 — when the board may reduce an assessment
- CGS §12-117a — appeal from the board to Superior Court
- CGS §12-63 — 70% of fair market value
- CT OPM — statutes governing property assessment and taxation
- CT OPM mill rates (this site’s FY2026 source)
- Your town assessor — start from the town mill-rate list
What this calculator does not do
The CT Property Tax calculator estimates municipal tax from the mill rate and a price you type. It does not file an appeal, value your house, or apply exemptions. A lower mill rate in another town does not change your assessment where you already own.