Picture two buyers standing at similar closing tables in the same month. One is buying a $585,000 colonial in Londonderry. The other is closing on a nearly identical home, same price, same square footage, in Merrimack. Their mortgage payments look almost the same on paper until the escrow line loads. The Londonderry buyer is putting aside roughly $705 a month for property taxes. The Merrimack buyer is setting aside noticeably more, every month, for the life of the loan.
Most people assume that gap is just a fact of small-town budgets, the kind of thing that varies for reasons nobody can quite explain. It isn't random. It traces back to a specific, ongoing development that most buyers comparing these towns have never heard of, and understanding it changes how you should read a tax rate table.
The Number on Every Closing Disclosure
Londonderry's 2025 property tax rate sits at about $14.47 per $1,000 of assessed value, a figure set by the New Hampshire Department of Revenue Administration after the town's 2025 revaluation. Put that side by side with the towns buyers in this price range typically cross-shop:
| Town | Rate per $1,000 (recent) |
|---|---|
| Londonderry | $14.47 |
| Bedford | $16.49 |
| Nashua | $16.83 |
| Merrimack | $18.53 |
| Hollis | $19.08 |
| Amherst | $20.07 |
On a home assessed near Londonderry's median market value of roughly $585,000, that translates to an annual bill around $8,465. The same assessed value under Merrimack's rate would run closer to $10,840 a year, a difference of about $200 a month sitting quietly in the escrow account long after the closing paperwork is filed away.
Expressed as an effective rate against market value, Londonderry lands around 1.61%, below both the Rockingham County median of 1.76% and the New Hampshire statewide median of 1.82%. For a state where property taxes carry more of the load precisely because there is no income or sales tax, a full point of daylight on the effective rate is not a rounding error.
What's Actually Different About Londonderry's Tax Base
The easy explanation is that Londonderry runs a tight budget. The real explanation is structural. A meaningful share of the town's tax base is commercial and industrial rather than residential, which means homeowners are not the only ones funding the school budget and municipal services. The Manchester-Boston Regional Airport sits partly within town limits. Distribution and manufacturing operations line the I-93 and Route 102 corridors. And the biggest single driver right now is Woodmont Commons.
Woodmont Commons is a 600-plus acre mixed-use development straddling I-93 between exits 4 and 5, approved for development back in 2013 and built out by Pillsbury Realty and Development. It is not a proposal on paper. According to 2024 reporting from the Union Leader, established businesses were already operating on-site, including the 603 Brewery and Beer Hall, a Derry Medical Center facility, and a bank, with new residential buildings such as The Baldwin slated for an official ribbon cutting later that year. Town officials at the time also outlined plans for more retail, more restaurants, a possible hotel, and additional residential space still to come.
At a Planning Board meeting covered in that same 2024 reporting, member Tony DeFrancesco summed up the town's read on the project plainly:
"It's good to see positive movement there."
That "positive movement" shows up directly in the tax rate. Every new commercial square foot at Woodmont Commons is taxable square footage that isn't sitting on a homeowner's bill. The project kept moving after that: a Planning Board session in April 2026, according to a recap posted by the local news outlet Town Underground, included a fiscal impact report showing continued tax revenue growth from the development, alongside new applications working through the pipeline for a retail car dealership and a 12-unit townhouse development.
This is the part most buyers miss when they're scanning a tax comparison chart. Londonderry's advantage over Nashua or Merrimack isn't a fixed feature of the town. It's a trend line tied to how much non-residential development keeps landing inside its borders, and right now that line is still moving in the same direction.
The Rate You See Today Isn't Fixed for Next Year
Here's the wrinkle that catches people during an actual transaction. The $14.47 figure is a 2025 rate. The 2026 rate won't be finalized by the Department of Revenue Administration until fall of this year, which means anyone budgeting off today's number is working from last year's math.
There's a second layer buried in how New Hampshire assesses property that makes town-to-town comparisons trickier than they look. Londonderry's assessed values, before the 2025 revaluation, sat at only about 85.3% of true market value, a ratio the town's assessing department confirmed and one the state uses to keep assessments and real-world sale prices aligned. The town completed a full revaluation for the 2025 tax year specifically to push assessments closer to 100% of market value, and as the town's own guidance points out, an increase in total assessed value generally pushes the tax rate down, since the same budget gets divided across a larger base.
What that means in practice: a low per-$1,000 rate on its own can be misleading if a town's assessments are running well below market value. The effective rate, which measures the tax bill against actual market value rather than the assessed figure, is the number that actually lets you compare Londonderry to Bedford or Amherst on equal footing. Londonderry's 1.61% effective rate holds up under that scrutiny. Not every town's advertised mill rate does.
Londonderry runs its full revaluation cycle every two years, according to the town's assessing department, which means the next reset after 2025 will land for the 2027 tax year. Between now and then, expect the nominal rate to shift again as Woodmont Commons keeps adding taxable commercial space and as the town-wide assessed value continues climbing with it.
What This Means If You're Comparing Towns
If you're weighing Londonderry against Merrimack or Nashua purely on sticker price, you're missing the part of the math that actually shows up in your monthly payment. The tax gap is real, it's documented, and it's tied to a development that is still under construction. That cuts both ways for a buyer's planning.
On one hand, the mechanism behind Londonderry's lower rate looks durable. Woodmont Commons has occupied businesses on the ground, not just permits on file, and the town's own fiscal reporting shows the commercial tax contribution growing rather than stalling. On the other hand, don't anchor a five-year budget to a number that resets on a two-year cycle. Ask your lender which year's rate they're using to estimate your escrow, and build in some room for the 2026 rate that gets set this fall.
For move-up buyers stretching between towns in this price band, the honest takeaway is that Londonderry's tax advantage is a genuine structural feature of the town, worth factoring into a side-by-side comparison the same way you'd factor in commute time or lot size. It just isn't a number to treat as permanently locked in.
A Short FAQ
Will Londonderry's 2026 tax rate be higher or lower than 2025? It isn't set yet. The Department of Revenue Administration typically finalizes each year's rate in the fall, and it depends on the town's finished budget and its updated total assessed value, including whatever new commercial square footage Woodmont Commons brings online this year.
Does a lower per-$1,000 rate always mean a lower actual tax bill? Not automatically. Compare effective rates against market value, not just the advertised mill rate, since towns with lower assessment ratios can post a misleadingly low headline number.
If you're weighing Londonderry against a neighboring town and want the real monthly numbers, not just the mill rate on a chart, Granite State Realty Group can walk through what a specific home's tax history and assessment actually look like before you write an offer. Request a free local market consultation and let's run the real math together.
