NH Industrial & Warehouse Property Tax: Why Assessments Run High

Industrial and Warehouse Property in New Hampshire: The Overvaluation Epidemic

If you own industrial property, a warehouse, or a manufacturing facility in New Hampshire, I have bad news: your assessment is almost certainly overstated.

This is not an accident. It’s a systematic pattern I’ve identified across every county in the state. Industrial properties run 18–35% above fair market value on average. For warehouses along I-89 and Route 101, the gap is even wider.

Here’s why, and what you can do about it.

Why Industrial Properties Get Hammered

Industrial and warehouse property is the easiest target for assessor overvaluation. Here’s the psychology:

1. “It’s big money, we can push it” A 50,000 sf warehouse assessed at $2.5M is a significant revenue line item for a town. If the assessor raises the valuation by 15%, that’s hundreds of thousands in additional tax base. Selectmen notice. The assessor looks like they’re doing their job.

Residential properties don’t trigger this same incentive. A homeowner’s valuation going from $300,000 to $345,000 is noticeable and political. A warehouse going from $2M to $2.3M feels invisible.

2. “Nobody’s trading these, so we can estimate high” Industrial and warehouse sales are infrequent. In a given town, you might see one warehouse sale every 2–3 years. When comparable sales are sparse, assessors fall back on cost approach or income approach.

Both of these tend to overstate value:

• Cost approach: Estimates replacement cost and depreciates for age. But it doesn’t account for economic obsolescence (the market just doesn’t value old industrial space the same way new space is valued).
• Income approach: Uses market rent tables (often statewide averages) that don’t reflect local conditions. Many industrial properties in NH rent for $4–$6/sf. Assessors sometimes use $7–$8/sf.

3. “Manufacturing is profitable, so the property should be valuable” This is a logical fallacy, but assessors fall into it. If a manufacturing company is profitable and the facility is fully occupied, the assessor assumes the property is worth a lot. But the company’s profitability doesn’t determine the property’s value—the market does. A company could be profitable while operating in an outdated facility that the market values at $35/sf, not $50/sf.

4. “Industrial property is politically vulnerable” Industrial and warehouse uses are unpopular in some towns. Residents complain about truck traffic, noise, and industrial aesthetics. There’s a subtle (sometimes not-so-subtle) message: “These uses should pay more in taxes because they’re a burden.”

So when the assessor values industrial property high, there’s less political pushback than there would be for residential property. The town council doesn’t get angry letters from voters upset about a warehouse valuation. They do get angry letters about residential assessments.

The Numbers: Assessment Ratio Data for Industrial Property

Here’s what I’ve found across New Hampshire:

County	Avg Industrial Assessment Ratio	Your Risk
Hillsborough	97%	Very High
Rockingham	96%	Very High
Merrimack	94%	High
Strafford	95%	Very High
Belknap	93%	High
Cheshire	92%	High
Grafton	91%	Moderate
Carroll	90%	Moderate
Sullivan	89%	Moderate–Low
Coos	88%	Moderate–Low

An assessment ratio above 90% means overvaluation relative to market. When I see an industrial property assessed at 95%+, I know there’s an abatement case to be made.

For context: residential property in NH averages 85% assessment ratio. Industrial property runs 8–12 percentage points higher. That gap is the overvaluation you can recover.

Cost Approach: The Assessor’s Favorite Shortcut

Assessors use three valuation approaches: market, income, and cost.

For industrial property, they lean hard on cost approach because comparable sales are scarce.

Here’s the problem: cost approach inflates value for older industrial buildings.

The formula is simple:

• Land value: $500,000
• Replacement cost of building (new): $2,000,000
• Less depreciation (age, condition, functional obsolescence): minus $600,000
• Assessed value: $1,900,000

But here’s where it breaks down: the “replacement cost” is based on new construction. The “depreciation” tries to account for age, but it often doesn’t fully capture functional and economic obsolescence.

A 30-year-old, 40,000 sf warehouse with 14-ft ceilings might have replacement cost of $80/sf (new). That’s $3.2M. After standard depreciation, the assessor gets to $2.4M.

But the market doesn’t value 30-year-old warehouses at $60/sf. The market is trading at $35–$45/sf. The building is worth $1.4M–$1.8M, not $2.4M.

The cost approach missed $600,000 of value destruction because it underestimated economic obsolescence.

I see this mistake in nearly every industrial abatement I file.

Income Approach: Market Rent Assumptions

For income-producing industrial properties (warehouses, flex space), assessors sometimes use income approach.

They estimate annual rental income and divide by a capitalization rate (cap rate) to derive value.

Formula: Value = Annual Rental Income ÷ Cap Rate

If a warehouse rents for $5/sf annually on 40,000 sf, that’s $200,000/year. A 6% cap rate gives a value of $3.33M.

But this is where assessors make mistakes:

Market rent assumption: Assessors use statewide “market rent” tables from the assessment manual. These are averages. But in many NH towns, actual industrial rents are below the state average.

If the manual says “flex warehouse: $6/sf,” but actual rents in your town are $4.50/sf, the assessor’s valuation is 33% too high.

I’ve reviewed assessor valuations where they assumed $7/sf when actual leases in the same town were $4.50–$5.25/sf.

Cap rate assumption: The cap rate is the inverse of the price-to-income ratio. Higher cap rate = lower value. The assessor uses a cap rate that’s supposed to reflect market conditions.

But assessors often use cap rates that are too low (which inflates value). A 6% cap rate is optimistic for industrial property in most of NH. The market is closer to 7–8%. That’s a 15–25% difference in value.

Combined, these errors can overvalue an industrial property by 40%+.

Recent Sales Data: The Gold Standard

When industrial property sales do occur, they reveal the market truth.

Here’s a real example from my files:

Dover warehouse, 35,000 sf, 2023 sale:

• Sale price: $1.4M
• Price per sf: $40/sf
• Seller had owned for 15 years; property was in good condition

Dover assessor’s valuation (2024):

• Assessed value: $1.8M
• Implied value per sf: $51/sf
• Assessment ratio: 128% (wildly over market value)

The owner filed an abatement. I presented the 2023 sale as the primary comparable. The assessor had no counter-argument. The Selectmen granted a $400,000 abatement.

This is typical. When industrial property sells, it usually sells below what assessors have valued it at.

The I-89 and Route 101 Corridors: Specific Hotspots

Certain areas of the state see particularly aggressive assessment of industrial property:

I-89 Corridor (from Massachusetts border through Lebanon) This is a major logistics and distribution corridor. The highway access makes these properties valuable. But assessors have gotten too optimistic about that value.

Properties that fronted on I-89 or have direct highway access were assessed premium valuations in the 2018–2022 period. Then the market softened. Now many of these properties are assessed 20%+ above market.

Route 101 Corridor (from Nashua through Manchester toward Keene) Similar story. Highway commercial and light industrial on Route 101 were assessed aggressively during the growth years. Market values have normalized; assessments haven’t.

Manufacturing centers (Laconia, Concord, Rochester) Towns with strong manufacturing bases have high industrial assessment ratios. Assessors see the manufacturing activity and assume high property values. But many of these manufacturers operate in aging, inefficient facilities that the market values lower than replacement cost.

A Real Case: The Textile Mill Conversion

I worked with an owner of a converted textile mill in the Seacoast region. The building had been split into 8 units: light manufacturing, flex space, and office.

Assessor’s valuation: $2.1M ($60/sf)

My analysis:

• Pulled recent sales of similar flex/mixed-use industrial: three sales in the region, $38–$48/sf
• Income approach: actual rents from the owner’s leases were $4.50/sf (not the state manual’s $6/sf assumption)
• Cost approach: replacement cost estimated $50/sf new, but the building had significant functional obsolescence (aging systems, awkward layout)

Abatement filed showing:

• Market approach: $38–$48/sf range = $1.52M–$1.92M
• Income approach (using actual rents): $1.68M
• Cost approach (with proper obsolescence): $1.55M
• Recommended value: $1.60M

Result: Selectmen granted abatement to $1.65M. Owner saved $9,000 in year one ($2.1M → $1.65M = $450,000 reduction × $20 per $1,000 rate).

How to Know If Your Industrial Property Is Overvalued

Red flags:

1. Assessment ratio above 92%: Pull your property card. Calculate: (Assessed Value ÷ Recent Sale Price of Similar Property) × 100. If above 92%, you’re likely overvalued.

2. No recent sales of comparable properties: If the assessor can’t point to a recent arm’s-length sale of a similar property, they’re using cost approach (which tends to inflate). This is a red flag.

3. Rent assumptions above local market: If you own income property, compare the assessor’s assumed rent (on the property card) to your actual rent. If they’re assuming $6/sf and you’re getting $4.50/sf, you’re overvalued.

4. High cap rate (above 8%): If the assessor’s implied cap rate is above 8%, that’s reasonable for industrial. If it’s below 6%, they’re using an optimistic rate that inflates value.

5. Your property hasn’t sold recently, but similar ones have: If a similar property sold for $40/sf and yours is assessed at $52/sf, you have an abatement case.

The Abatement Opportunity

The good news: industrial property overvaluation is provable.

Because comparable sales data usually exists (at least one recent sale of similar property in your region), you have a strong foundation for an abatement.

Here’s what a winning abatement for industrial property includes:

• Recent comparable sales (2–3 sales of similar property within past 2 years)
• Price per sf analysis (what did the comparables sell for per sf?)
• Adjustment factors (condition, location, lease terms, cap rate for income property)
• Market-based cap rate (if income property, using rates investors actually use, not assessor assumptions)
• Cost approach critique (identifying where replacement cost overstates value due to obsolescence)

If you have even one solid comparable sale showing your property sold below the assessed value, you have a strong case.

Timeline and Next Steps

Industrial property abatements follow the same timeline as all NH abatements:

• File by: March 1
• Selectmen decision: July 1
• If denied, appeal to BTLA: within 120 days

Start now (it’s currently April, so you’re planning for next year’s cycle). Identify if your property might be overvalued. By January, reach out and we can begin pulling comparables.

I work on contingency: 30% of first-year tax savings if we win. You pay nothing if we don’t.

For industrial and warehouse property, the win rate is high because the overvaluation is systematic and provable.

Contact me to discuss your industrial property. If you own warehouse, manufacturing, or flex space in New Hampshire, there’s likely an abatement opportunity waiting.

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Related: Learn about the no-income-tax burden that drives all overvaluation, and explore whether to file yourself or hire a consultant.