Common Area Maintenance charges are the primary mechanism for recovering operating expenses from tenants. When CAM charges are missed, the property absorbs the cost. The loss is not a one-time event. It repeats every month until the error is found.
Most CAM leakage is not discovered by the property manager. It is discovered by the tenant's auditor, the owner's accountant, or a new controller who cannot reconcile the numbers. By then, the loss is months or years old.
This article identifies the five places where CAM charges are missed and explains how to close the gaps.
Leakage Point 1: Expenses Never Billed
What happens: A recoverable expense is paid by the property but never included in the CAM pool.
Why it happens:
- The invoice is coded to a non-recoverable account
- The expense is not flagged as recoverable in the accounting system
- The person coding the invoice does not know the lease allows recovery
- The invoice is lost in email and never entered
The impact: The property absorbs 100% of the expense. The tenant pays nothing.
Example: A $4,200 parking lot repair is coded to "Capital Improvements" instead of "Recoverable Repairs." The lease allows recovery of parking lot maintenance. The expense is never billed. The property absorbs $4,200.
Leakage Point 2: Incorrect Allocations
What happens: A recoverable expense is billed, but the tenant's share is calculated incorrectly.
Why it happens:
- The pro-rata percentage is outdated
- The denominator (total leasable square footage) changed and was not updated
- A new tenant moved in and the percentages were not recalculated
- A tenant expanded and their percentage was not adjusted
The impact: Some tenants overpay. Others underpay. The property absorbs the net difference.
Example: A retail center has 10 tenants. Tenant A's lease says 12.5% of CAM. The building is remeasured and Tenant A's space is now 11.2% of the total. The spreadsheet is not updated. Tenant A is overbilled by 1.3% every month. Over three years, the overbilling is $14,000. The tenant disputes. The property owes a refund plus interest.
Prevention: Pro-rata percentages are stored as structured data and updated automatically when the lease or the building changes.
Leakage Point 3: Outdated Tenant Percentages
What happens: Tenant percentages are set at lease signing and never updated.
Why it happens:
- The lease amendment changing the percentage is filed but not entered
- A remeasurement changes the square footage but the percentage is not recalculated
- A tenant's expansion adds space but the denominator is not adjusted
- The spreadsheet was built years ago and nobody remembers the source
The impact: The wrong amount is billed every month. The error compounds.
Example: A tenant signs a lease for 5,000 square feet in a 40,000 square foot building. Pro-rata share: 12.5%. The tenant expands to 7,500 square feet. The amendment is signed. The spreadsheet is not updated. The tenant is billed at 12.5% instead of 18.75%. The property under-recovers by 6.25% of CAM every month. Over a 3-year remaining term, the loss is $22,500.
Prevention: Percentages are recalculated automatically when the lease or the space changes. The system tracks the amendment and updates the denominator.
Leakage Point 4: Missed Recoverable Costs
What happens: An expense that the lease allows to be recovered is treated as non-recoverable.
Why it happens:
- The lease exclusion list is not applied correctly
- A new expense category is not mapped to the recovery rules
- The person coding the expense does not have access to the lease
- The lease language is ambiguous and the conservative approach is to exclude
The impact: The property absorbs expenses that should be passed through.
Example: A lease allows recovery of "all operating expenses, including but not limited to landscaping, security, and parking lot maintenance, but excluding capital improvements and depreciation." A $3,800 security system upgrade is coded as a capital improvement. The lease defines capital improvements as "improvements with a useful life exceeding five years." The security system has a useful life of three years. It is recoverable. The property absorbs $3,800.
Prevention: Expenses are classified against the specific lease language. Ambiguous items are flagged for human review, not silently excluded.
Leakage Point 5: Cap and Exclusion Violations
What happens: A controllable expense cap is exceeded and the excess is not absorbed by the property. Or an excluded expense is included in the pool and the tenant is overbilled.
Why it happens:
- The cap is not tracked in the accounting system
- The cap base year is wrong
- The cumulative vs. non-cumulative structure is misunderstood
- An excluded expense is miscoded and enters the pool
The impact: Cap violations mean the property absorbs expenses that should be billed. Exclusion violations mean tenants overpay and the property faces refund claims.
Example: A lease has a 5% controllable expense cap, non-cumulative, base year 2023. In 2025, controllable expenses increased 8%. The cap limits the recovery to 5%. The property should absorb 3%. The spreadsheet does not apply the cap. The tenant is billed for the full 8%. The tenant audits. The property owes a refund for the 3% overbilling plus the dispute costs.
Prevention: Caps are enforced automatically. The system tracks the base year, the rate, and the structure. Excluded expenses are identified and removed before the pool is calculated.
The Permanent Loss Problem
CAM errors are not recoverable after the fact. Most leases have a dispute window of 30 to 90 days after the reconciliation statement. If the error is not found before the statement is final, the loss is permanent.
Recovery requires:
- Audit rights under the lease
- Tenant cooperation or legal action
- Restatement of prior periods
- Reputational damage
The cost of recovery usually exceeds the amount recovered. Most owners do not pursue past CAM errors.
The Alternative: Validation at Entry
Periodic CAM reconciliation is done once a year. The errors accumulate for 12 months before they are found.
- Every invoice is classified against the lease terms at entry
- Every percentage is current and validated
- Every cap is enforced as expenses are incurred
- Every exclusion is applied before the pool is calculated
- Every month the reconciliation is current, not annual
The annual reconciliation becomes a confirmation, not a reconstruction.
Conclusion
CAM charges are missed because the process is manual, the rules are complex, and the systems do not talk to each other. The five leakage points — expenses never billed, incorrect allocations, outdated percentages, missed recoverable costs, and cap violations — are predictable and preventable.
The fix is not more review. It is a system that validates every charge against the lease before it is billed.
Komod.ai is an AI-native operating layer for the commercial real estate back office. The platform reads leases, invoices, and bank activity; performs deterministic calculations; and stages completed work for human approval. Nothing posts without you.