CAM — Common Area Maintenance — is one of the most misunderstood line items in a commercial lease. It affects your total occupancy cost every year of the lease term, and it's almost always negotiable.
What CAM actually is
CAM stands for Common Area Maintenance. It's the tenant's share of the operating expenses a landlord incurs to run the building and its shared spaces. In a multi-tenant property, each tenant pays a prorated share based on the percentage of the building they occupy.
Typical CAM expenses include:
- Property management fees
- Landscaping and parking lot maintenance
- Common area utilities, lighting, and cleaning
- Security and snow removal
- HVAC maintenance for shared systems
- Insurance and property taxes (in triple-net lease structures)
CAM is charged in addition to base rent. It's stated as a per-square-foot annual amount and billed monthly alongside rent.
How CAM actually works
At the start of each year, the landlord estimates total CAM expenses and bills the tenant their pro-rata share in twelve monthly installments. At year-end, the landlord reconciles actual expenses against estimates. If actual exceeded estimate, the tenant owes the difference. If actual came in under estimate, the tenant is credited or refunded.
This reconciliation structure is where CAM can become expensive quickly. Without protection, a tenant has no control over how much CAM increases year over year — and some categories of expense are structurally prone to rising faster than inflation.
What matters for tenants
Three things deserve attention on CAM:
Operating expense caps. A well-structured lease includes a cap on how much CAM can increase annually — typically a percentage over the prior year, with categories like property taxes and insurance excluded from the cap (because they're genuinely outside the landlord's control). Caps protect tenants from runaway CAM exposure over a multi-year term.
CAM audit rights. Tenants should have the contractual right to audit the landlord's CAM calculations. Without this, the tenant is paying whatever the landlord invoices with no ability to verify accuracy.
Exclusions. Certain expenses should not be passed through to tenants — capital improvements that benefit the landlord's ownership position, marketing costs for the property as a whole, or costs related to leasing vacant space. These exclusions are negotiable and should be specified in the lease.
Every one of these protections is standard to negotiate. They're not unusual asks. They are, however, often absent from first-draft lease language — which is one reason why close documentation review matters.