The base rent is $22 per square foot. The total occupancy cost is $32 per square foot. The $10 difference is the 'triple net' — property taxes, insurance, and maintenance that you pay on top of the rent. Understanding what's in those nets, and how to cap them, is the difference between a sustainable lease and a steadily increasing one.
NNN Means You Pay Three Operating Costs Above Your Base Rent
In a triple-net lease, the tenant pays base rent plus three additional categories of expense: property taxes (typically $3–$6/sq ft/year in most suburban markets; higher in urban cores or high-tax states); building insurance ($0.50–$1.50/sq ft/year for standard commercial property coverage); and common area maintenance — CAM — which includes landscaping, parking lot maintenance, building management, janitorial service for common areas, and shared utility costs ($4–$8/sq ft/year). Combined, these 'nets' often add $7–$15/sq ft annually to the quoted base rent. For a tenant occupying 5,000 sq ft at $20/sq ft base rent, NNN charges might add $50,000–$75,000/year to their annual occupancy cost.
Property Tax Pass-Throughs Create Unexpected Annual Volatility
Property taxes are the most volatile NNN component. A commercial property that hasn't been sold in years may have a low assessed value — and therefore low taxes — at the time you sign. If the property sells during your lease term (which is common, as commercial real estate trades regularly), the sale price triggers a reassessment. A property assessed at $3 million that sells for $6 million may see property taxes double after reassessment. For a tenant paying 12% of a building's taxes (their pro-rata share), a $50,000 annual tax increase means $6,000/year more in NNN charges — with no notice, no cap, and no recourse. Negotiate a base-year tax provision capping your contribution at current-year taxes with your share of increases only above that level.
Understanding Your Pro-Rata Share Calculation
Your NNN charges are proportionate to your percentage of the building's total leasable area. If you occupy 3,000 sq ft in a 25,000 sq ft building, you pay 12% of all NNN expenses. But the denominator — that 25,000 sq ft figure — matters. Make sure it's the total leasable area, not the gross building area (which includes non-leasable space like mechanical rooms, lobbies, and stairwells). Confirm that vacant space isn't reducing the denominator and therefore inflating your percentage. In a building that's 30% vacant, make sure you're not paying 30% more NNN than when the building is full — most leases include a gross-up provision, but verify.
NNN Leases for Standalone Buildings Work Differently
A true single-tenant NNN lease — a freestanding restaurant building, a standalone pharmacy, a single-user warehouse — is different from a NNN lease in a multi-tenant center. In a single-tenant NNN, you're responsible for all property costs: taxes, insurance, and all maintenance and repair, including the building's structural components, roof, and major systems. There's no pro-rata calculation — you pay 100% of everything. In exchange, single-tenant NNN leases typically have lower base rents, recognizing that the tenant is effectively operating the entire property. Know which version you're signing.
Negotiating NNN Protections: Caps, Audits, and Exclusions
Key NNN negotiating provisions: a 5% annual cap on controllable operating expense increases (maintenance, management — not taxes or insurance); an explicit exclusion list for non-reimbursable costs (capital improvements, landlord financing costs, landlord income taxes, leasing commissions); an annual audit right with the landlord paying your audit costs if overcharges exceed 5% of amounts billed; and a requirement that the landlord provide prior-year actual expense statements before signing so you know the baseline. Get the landlord's current-year estimated NNN budget in writing as an exhibit to the lease — so there are no surprises in year one.
Key Takeaways
- NNN charges typically add $7–$15/sq ft annually above base rent — model this before signing
- Property tax reassessment after a building sale can double your tax pass-through with no warning
- Negotiate a base-year tax provision, controllable expense cap, and explicit exclusion list before signing
- Single-tenant NNN leases make you responsible for 100% of all building costs including structural
- Get the prior 2 years of actual NNN expenses before signing — the landlord's estimate is always optimistic
Frequently Asked Questions
- What is the difference between NNN, modified gross, and gross leases?
- In a gross lease, the landlord covers all operating expenses and you pay one fixed rent. In a modified gross lease, some expenses are included and others pass through — negotiated by line item. In a NNN lease, you pay all three nets separately. The key difference is who bears the risk of expense increases.
- What is an absolute net lease?
- An absolute net lease (or 'bondable' lease) makes the tenant responsible for all property costs including structural repairs, roof replacement, and even rebuilding after casualty. These are most common in single-tenant freestanding buildings. They offer the lowest base rent but the most financial risk.
- Can I audit NNN charges like CAM charges?
- Yes. Your lease should give you audit rights for all NNN expense pass-throughs including taxes, insurance, and CAM. Exercise them annually, particularly for property tax charges — landlords sometimes pass through the full tax bill without adjusting for tenant-specific abatements.
- What is a net lease for a single-tenant property?
- Single-tenant NNN leases (like those used for freestanding fast food restaurants or dollar stores) often approach absolute net structures, with the tenant responsible for virtually all building maintenance. These leases are standard in net lease investment properties and the terms are usually non-negotiable for national tenant requirements.
- Is a NNN lease better or worse for tenants?
- It depends on the actual expense levels and your negotiating skills. If operating expenses are low and stable, NNN can result in lower occupancy cost than a gross lease. If expenses are high, variable, or poorly managed by the landlord, NNN is worse. Always get historical expense data before signing.