Triple net leases — commonly referred to as NNN leases — require tenants to pay their share of property taxes, insurance, and common area maintenance on top of base rent. These additional charges can represent a significant portion of total occupancy costs, and errors in how they are calculated or billed are common.
What Is a Triple Net Lease?
A triple net lease is a commercial lease structure where the tenant is responsible for three categories of property expenses in addition to base rent:
- Property taxes — The tenant's pro rata share of real estate taxes assessed on the property
- Insurance — The tenant's share of property insurance premiums, including liability and casualty coverage
- Common area maintenance (CAM) — Operating expenses for shared areas including landscaping, cleaning, security, and repairs
NNN leases are standard in retail and commercial real estate. While they offer landlords predictable cost recovery, they shift financial risk to tenants — making it critical for tenants to verify that each charge complies with their lease terms. For a deeper look at how CAM charges work, see our detailed guide.
Common NNN Billing Issues
Because NNN leases cover multiple expense categories, there are more opportunities for billing errors and overcharges. Some of the most common issues tenants encounter include:
CAM Discrepancies
- Management fees exceeding the lease-defined cap percentage
- Capital improvements classified as maintenance and passed through as CAM
- Expenses excluded by the lease appearing on reconciliation statements
- Year-over-year CAM increases that exceed contractual escalation caps
Tax Discrepancies
- Property tax bills allocated using incorrect square footage or pro rata share percentages
- Tax reassessments passed through without adjusting for exemptions or appeals
- Tenants billed for tax increases related to landlord improvements the lease excludes
Insurance Discrepancies
- Insurance premiums increasing significantly without explanation or documentation
- Coverage types not required by the lease included in tenant pass-throughs
- Insurance costs for landlord-owned improvements billed to tenants
Many of these issues are documented in our guide to common CAM overcharges tenants miss and our overview of hidden costs in NNN leases.
How LeaseGuard Helps Audit NNN Charges
LeaseGuard is designed to help commercial tenants review their lease charges quickly and identify potential discrepancies. While the platform focuses on CAM clause analysis and reconciliation statement review, these are typically the largest and most error-prone components of NNN lease expenses.
The audit process works as follows:
- Upload your commercial lease PDF along with one or more annual CAM reconciliation statements from your landlord
- LeaseGuard extracts key provisions — CAM caps, admin fee limits, excluded expenses, and pro rata share terms
- The system compares billed charges against your lease terms and flags potential discrepancies
- Review findings and download a detailed audit report with source-level evidence
For a complete walkthrough of the audit process, see our guide on how to audit CAM charges. You can also review our CAM reconciliation guide for details on how reconciliation statements work.