How Connecticut Towns Decide What Your House Is Worth

Every few years a letter from town hall tells you what your house is worth, and the number rarely matches anything else in your life. It sits below your neighbor's sale price, above what you paid, and nowhere near the figure your lender produced when you refinanced. Homeowners across Fairfield County read these notices and wonder whether the town knows something they do not.

The confusion is understandable, because the town's number answers a much narrower question than most people assume. Here is how Connecticut municipalities actually arrive at your assessment, why it is usually out of date by design, and what to do when you believe it is wrong.

Three Numbers That Get Mistaken for Each Other

Market value is what a willing buyer would pay for your home today. A bank appraisal is one professional's opinion of that value on one date, ordered for one loan. Your assessment is neither. It exists for exactly one purpose: dividing your town's tax levy fairly among property owners. It is not trying to tell you what your home would sell for this weekend, and reading it that way is where most of the confusion starts.

The 70 Percent Rule

Connecticut law sets every assessment at 70 percent of a property's fair market value as of the town's last revaluation date. If the town concluded your home was worth $1 million at that point, your assessment reads $700,000. Nobody at town hall thinks your house is worth $700,000; the discount is written into the statute and applies to every property in the state.

This is the single most misread number in Connecticut real estate. Divide your assessment by 0.7 and you recover the town's actual opinion of value. An assessment that seems 30 percent too low is usually exactly where the law says it should be.

A Snapshot That Ages for Five Years

State law requires each town to revalue all real estate at least once every five years, effective as of an October 1 assessment date. Between revaluations, the market value opinion behind your assessment is frozen at that date. Prices on your street can move every month; your assessment will not, because it is a timestamp, not a ticker.

In a market that has climbed the way Fairfield County's has in recent years, that means most assessments imply values well below what homes currently command. That is not the assessor falling behind on the job. It is the system working as designed, and it corrects in one jump at the next revaluation. Towns must also physically inspect each property at least once every ten years, which is why a data collector occasionally appears at the door with a clipboard.

How the Number Actually Gets Set

No one walks through your house with a checklist at revaluation and prices it like a buyer would. Towns, usually working with a revaluation company under the assessor's supervision, value thousands of properties at once through mass appraisal. Your property record lists the facts: living area, land, bedrooms and baths, age, condition, construction grade. The town groups similar properties by neighborhood, studies the arm's-length sales that occurred around the revaluation date, and calibrates a model so its predicted values track what homes genuinely sold for. Your new value comes out of that model, notices go out, and after informal hearings the numbers settle into the grand list.

It is a system built to be right on average across an entire town. Your house is one data point inside it, which is exactly why it can be wrong about your house specifically: an unrecorded renovation, an overstated square footage, a condition problem the model cannot see.

Why a Higher Assessment Does Not Mean a Higher Tax Bill

Your annual tax is the assessment multiplied by the mill rate, which is the tax per $1,000 of assessed value. Suppose a town's rate is 20 mills: a $700,000 assessment produces a $14,000 bill. The mill rate is the lever people forget. When a revaluation raises assessments across town, the town does not suddenly collect more money; the levy is set by the budget, and the mill rate typically resets downward against the larger grand list.

What actually changes your bill is how your value moved relative to everyone else's. If the average home in town rose 25 percent at revaluation and yours rose 25 percent, your share of the levy is unchanged. If yours rose 40 percent while the town averaged 25, your share grew, and that is the number worth scrutinizing.

If You Think the Town Got It Wrong

Start with your property card, available from the assessor's office and often online. Confirm the basics: square footage, bathroom count, finished basement area, condition rating. Factual errors are more common than people expect, and they are the easiest wins.

After a revaluation, you will usually get a window for an informal hearing with the revaluation company before values are finalized. Use it. For a formal challenge, Connecticut gives you the Board of Assessment Appeals: a written application due by February 20 in most towns, with some extending the deadline to March 20, and hearings the following month. Bring evidence tied to the revaluation date, not to today: comparable sales from that period, a private appraisal, photos of condition issues. The argument that persuades a board is not that your taxes are too high; it is that the market value opinion behind the assessment was too high on the date it was set.

If the board's decision still leaves a serious gap, the remaining step is an appeal to Superior Court within two months. For most homeowners that only makes sense when the numbers involved are large.

None of this tells you what your home would bring if you listed it in September. The assessment is a tax allocation with a five-year clock; the market is live. If you are weighing a sale, or simply curious how far the town's snapshot has drifted from current conditions, ask for a real analysis of recent sales on your street. I prepare those for Fairfield County homeowners regularly, and the gap between the two numbers is often the most interesting part of the conversation.