The difference between nnn vs modified gross vs full service lease structures determines what a Mesa office tenant pays each month beyond base rent. Each structure shifts property taxes, insurance, and operating costs between parties differently, and misreading the lease type generates unexpected expenses at year-end reconciliation.
By David Pierce, MHG Commercial
The Three Lease Structures Mesa Office Tenants Encounter
In commercial real estate, lease structure defines who pays building operating expenses. The three primary structures a Mesa office tenant encounters are the triple net lease, the gross lease (also called the full service lease), and the modified gross lease. Each represents a different financial arrangement between landlord and tenant.
The nnn vs modified gross vs full service distinction comes down to which party absorbs variable operating costs over the lease term. Lease structure also determines how predictably you can budget occupancy costs year to year. A gross lease produces a fixed expense line. A triple net lease produces a variable one. Modified gross leases fall between the two, depending on what was negotiated and when the base year was set.
Knowing which structure a property uses before touring it lets you compare options on equal terms. A NNN rate and a full service rate quoted for the same submarket can look similar on paper but diverge significantly once pass-through expenses are added. Tenants who proceed without understanding the structure often discover the gap only after year-end expense reconciliation.
What Triple Net Leases Require From Mesa Office Tenants
NNN leases, or triple net leases, require tenants to pay base rent plus three building expense categories: property taxes, building insurance, and common area maintenance. These pass-through costs are charged on top of base rent, calculated on a pro-rata basis using the tenant's leased square footage as a percentage of the building's total rentable area.
Property taxes on commercial real estate in Maricopa County are assessed against the property's full cash value. Under nnn leases, any assessment increase passes directly to tenants in proportion to their leased share. A county reassessment or a building sale at a higher valuation raises the tenant's property tax share mid-lease, which is one of the more common cost surprises in triple net structures.
Common area maintenance under a triple net structure covers parking upkeep, exterior landscaping, shared corridor cleaning, elevator service, exterior lighting, and shared building systems. Costs vary with building age and deferred maintenance history. Triple net leases are standard in retail strip centers and single-tenant net lease investment properties. In Mesa's office market they appear primarily in single-tenant buildings and flex-industrial spaces. Multi-tenant Class A and B office buildings use this structure less frequently.
How Full Service Gross Leases Simplify Tenant Budgeting
A full service gross lease quotes one rate per square foot covering base rent plus the landlord's cost for property taxes, building insurance, utilities, janitorial services, and common area maintenance. The tenant pays one predictable monthly amount for the lease term.
Landlords underwriting gross leases price in an expense buffer to cover cost increases during the term. A gross lease insulates tenants from property tax reassessments and rising maintenance costs that would otherwise pass through under a net lease. It is the most straightforward comparison point when evaluating nnn vs modified gross vs full service alternatives on the same property, because rates compare directly without expense adjustments.
Full service gross leases are more common in professionally managed Class A office buildings in the Mesa, Tempe, and Scottsdale corridors where landlords prefer centralized control over building operations.
NNN vs Modified Gross vs Full Service: Expense Sharing in the East Valley
A modified gross lease splits operating expenses between landlord and tenant on terms negotiated at signing. There is no industry-wide standard definition. One version requires tenants to cover utilities and janitorial costs while the landlord retains property taxes, insurance, and common area maintenance. Another uses a base year structure.
In a base year modified gross lease, the landlord absorbs all operating costs in the first lease year, establishing the base year benchmark. In subsequent years, the tenant pays a pro-rata share of operating cost increases above that level. If property taxes rise or common area maintenance costs increase, the tenant absorbs a growing share each year beyond the base year.
Review actual expense statements from the proposed base year before agreeing to the structure. A base year set during a low-cost period increases tenant exposure significantly as operating costs rise. Modified gross leases are the most common office structure in Mesa, Chandler, and Gilbert for mid-tier multi-tenant space. They give landlords partial cost recovery while offering tenants more budget clarity than nnn leases. Expect this structure as the default when touring office product in most East Valley submarkets.
Common Area Maintenance: What Landlords Include and What Is Negotiable
Common area maintenance charges are the most contested line item in commercial real estate leases. CAM covers shared building spaces and systems: lobbies, hallways, parking areas, landscaping, exterior lighting, elevators, and building-wide HVAC infrastructure serving all tenants. Each tenant pays a pro-rata CAM share based on leased square footage relative to total building area.
The Building Owners and Managers Association (BOMA International) publishes the Office Standard, last updated in 2017, which provides the rentable area measurement methodology most institutional Phoenix metro landlords use for pro-rata CAM calculations.
What landlords include in CAM varies. Some add property management fees, administrative overhead, or capital expenditures for roof or HVAC replacement. Industry practice typically excludes major capital expenditures from operating expense pass-throughs, but individual leases differ. Tenants have audit rights under most commercial leases allowing verification of landlord expense claims. Exercise those rights when CAM charges increase year over year without a clear explanation. Request a three-year CAM history and itemized breakdown before signing any net lease or modified gross agreement.
Under a gross lease, common area costs are absorbed into the quoted rate. Under a modified gross structure, CAM may be capped or excluded by negotiation. Under triple net leases, common area maintenance is fully variable and tenant-borne.
Frequently Asked Questions
What is the difference between a net lease and a gross lease for a Mesa office tenant?
A net lease, including triple net leases, requires tenants to pay base rent plus property taxes, building insurance, and common area maintenance as separate pass-through charges. A gross lease combines those costs into one all-in quoted rate. Net lease tenants absorb more cost variability. Gross lease tenants pay a built-in premium for that predictability.
How does a modified gross lease base year affect total occupancy cost?
The base year sets the operating cost benchmark. In years when actual expenses exceed that level, the tenant pays a pro-rata share of the increase. A base year set during a low-cost period creates more tenant exposure in subsequent years. Review actual base year expense statements before agreeing to a modified gross structure.
What does common area maintenance typically cover in a Mesa office building?
Common area maintenance in a Mesa commercial property typically covers parking upkeep, landscaping, corridor cleaning, lobby maintenance, elevator service, exterior lighting, and building-wide HVAC infrastructure. Some landlords include property management fees in their CAM definition. Negotiate exclusions for capital expenditures before signing any commercial real estate lease.
Are triple net leases common for Mesa office tenants?
Triple net leases are more prevalent in retail and single-tenant commercial real estate than in multi-tenant office buildings. In Mesa's office market, nnn leases appear primarily in single-tenant buildings and flex-industrial products. Most multi-tenant East Valley office properties use modified gross or gross lease structures.
Can tenants negotiate CAM caps or expense exclusions in a commercial lease?
Yes. CAM caps, expense exclusions, audit rights, and the definition of what qualifies as common area maintenance are all negotiable in commercial real estate. Leverage depends on market conditions, building occupancy, and lease term length. Tenants represented by a commercial broker consistently secure better expense terms than unrepresented tenants.
Work With a Pierce CRE Broker Before Signing Your Mesa Office Lease
Your lease type determines your financial exposure for the entire term, and clarifying nnn vs modified gross vs full service terms is the first step in any commercial real estate office search. Whether evaluating a first Mesa office lease or negotiating a renewal in Chandler or Gilbert, contact Pierce CRE to review your lease structure and total occupancy cost before you commit.