The tax bills went out on July 1. They were due August 1. And across Old Greenwich, plenty of homeowners opened envelopes that didn't match the headline they'd been reading all spring: that Greenwich had just adopted the lowest mill rate in Connecticut.
That headline is true. The mechanism behind it is not what most people assume. If you own in Old Greenwich, or you're comparing it against Riverside, Darien, or another Fairfield County town while house hunting, the gap between "lowest mill rate in the state" and "what I actually owe" is worth understanding before you run your own numbers.
What Actually Changed On July 1
Every five years, Connecticut requires towns to revalue all real estate to keep assessments aligned with the market. Greenwich's 2025 revaluation reset every property's assessed value as of October 1, 2025, with notices mailed to owners that November. That new assessment is the one showing up on this year's tax bill, the first under the new numbers.
Town-wide, the average residential assessment rose by roughly 27 percent. At the same time, the Board of Estimate and Taxation unanimously approved a fiscal 2026-27 budget of $542.4 million and sent it to the Representative Town Meeting that spring, up from about $516 million the year before, an increase of roughly 5 percent. To keep the town's total tax collection from ballooning by 27 percent alongside assessments, the BET set a mill rate of 10.12, down from 12.041, which the Greenwich Democratic Town Committee reported in an April 2026 update gives Greenwich the lowest mill rate in the state.
Run the arithmetic and it checks out almost exactly: a budget that grew about 5 percent, spread across a grand list that grew about 27 percent, produces a mill rate cut in the same range as the one the BET landed on, a drop of roughly 16 percent. The town's math is sound. It's also town-wide math, and town-wide math is not your math.
The Part the Press Release Leaves Out
A revaluation doesn't raise or lower how much a town collects. As BET Chair David Weisbrod explained in a February 2026 letter, the board sets the final mill rate each May once the budget cycle wraps, and that rate gets applied against the new assessments to produce the actual bill. What the process does is redistribute the same total burden according to whose property value moved the most.
If your home's assessed value rose by exactly the town average of 27 percent, the rate cut offsets it and your bill lands close to flat. If your value rose less than 27 percent, you likely see a real decrease. If it rose more than 27 percent, the rate cut isn't enough to cover the gap, and your bill goes up even in a year the town is publicly celebrating record-low rates.
A town-wide rate cut and a lower personal tax bill are two different claims. The second one only follows from the first if your neighborhood tracked the town's average. Old Greenwich rarely does.
Why Old Greenwich Is Exactly the Kind of Neighborhood This Catches
Local coverage of the revaluation flagged this early. A pre-revaluation analysis from October 2025 singled out walkable, high-demand pockets of town, specifically naming Old Greenwich, Riverside, and Cos Cob, as the areas most likely to see assessment increases that outpace the town-wide figure. The reasoning holds up against what was actually happening in the OG market heading into the assessor's October 1, 2025 valuation date.
In January 2026, eight Old Greenwich homes closed at a median price of $4.2 million, up 6.6 percent from the same month a year earlier, with average time on market compressing from 105 days to just 30. Neighborhood-level reporting on the first quarter of 2026 placed Old Greenwich and Cos Cob among the fastest-moving submarkets in town, both averaging under 40 days on market with sale-to-list ratios above 103 percent, meaning buyers were routinely bidding past asking price. That combination, fast turnover and consistent overbidding, is the exact signature of a submarket outrunning the town average, which is what a revaluation is designed to detect and price in.
None of this is unique to any one street. It's a function of what's been true about Old Greenwich for years: walkable village access, a short walk to the Metro-North platform, and beach rights at Greenwich Point put steady upward pressure on demand that a lot of the rest of the grand list simply didn't see over the same five-year cycle.
What This Means If You're Comparing Neighborhoods or Towns
If you're weighing Old Greenwich against a neighboring town, the town-wide mill rate is only half the comparison. Here's where things stood on the rate side going into this cycle, using the most recently published figures for each town.
| Town | Mill Rate | Fiscal Year |
|---|---|---|
| Greenwich | 10.12 | 2026-27 (newly adopted) |
| Darien | 15.48 | 2025-26 (most recent published) |
| New Canaan | 16.69 | 2025-26 (most recent published) |
| Stamford (District A) | 27.17 | 2025-26 (most recent published) |
Greenwich's rate is genuinely the outlier here, and that gap isn't going away. But the number that actually determines your bill is your specific assessed value times that rate, not the rate on its own. Darien and New Canaan complete their own revaluation cycles on a different schedule, so their published rates will shift too as those towns work through the same relative-appreciation math Greenwich just finished.
For a buyer running the numbers on an Old Greenwich listing against a comparable property in Darien or Riverside, that means the useful question isn't "which town has the lower mill rate." It's "what is this specific property's post-revaluation assessed value, and how does that pair with the current rate." A seller's most recent tax bill, if it predates July 2026, no longer reflects the number a buyer should be budgeting against.
Three things worth asking for on any Old Greenwich property right now, whether you're the one selling or the one making an offer:
- The current assessed value from the 2025 revaluation, not last year's figure
- Confirmation of whether the property sits in a sewer district, since those carry small additional millages on top of the base rate
- A written estimate of the full-year tax bill at 10.12 mills, not an estimate carried over from the old 12.041 rate
Why This Matters Past This Tax Cycle
Connecticut runs on a five-year revaluation clock, and the appeal window for this cycle's assessments closed February 20, 2026. If your assessment already reflects the new number and you believe it's off, your recourse now runs through the standard Board of Assessment Appeals process for future cycles, not this one. For anyone buying into Old Greenwich this year, the assessment you inherit is the one already set. What you're really pricing in is how the town's next revaluation, five years out, is likely to treat a neighborhood that has consistently run hotter than the town-wide average.
That's the kind of detail that doesn't show up on a listing sheet and rarely comes up until closing, which is exactly why it's worth understanding before you're the one signing at the table. Staging and photography get a buyer in the door. Getting the carrying-cost math right before an offer goes in is a different kind of preparation, and it's the kind that saves both sides a surprise later.
Frequently Asked Questions
Does a lower town-wide mill rate guarantee a lower personal tax bill? No. The rate cut offsets the town-wide average assessment increase. If your specific property's assessed value rose faster than that average, roughly 27 percent this cycle, your bill can still increase even as the rate drops.
How do I find a property's current assessed value in Old Greenwich? The Town of Greenwich Assessor's Office maintains updated records reflecting the 2025 revaluation, effective on the July 2026 tax bill. Sellers can also provide the most recent assessment notice directly.
Is there still time to appeal a 2025 revaluation assessment? The formal appeal window for this cycle closed February 20, 2026. Future concerns would be addressed at the next scheduled revaluation or through the standard annual appeals process for new assessments going forward.
If you're weighing an Old Greenwich purchase against another Fairfield County town, or you're getting ready to list and want the carrying-cost numbers presented clearly to buyers from day one, Nora Giovati can walk through the current assessment and what it means for your specific address. Show me homes or list my property, contact Nora today.
