Medical Office CAM Charges: Why MOBs Pay $15-20+/SF and Where Overcharges Hide
Medical office tenants pay more in CAM charges than any other property type. CBRE's Healthcare Real Estate Market Report (2024) puts Class A medical office building (MOB) CAM charges at $15–$22 per square foot per year for on-campus facilities and $12–$18/SF for off-campus buildings. For a 4,000-square-foot primary care practice, that's $60,000 to $88,000 per year in CAM alone, before rent. How much of that total reflects costs that belong to specific tenants, not shared building operations?
Some of that premium is legitimate. Medical buildings have specific infrastructure requirements: specialized HVAC filtration for infection control, backup power systems, medical gas infrastructure, and higher cleaning standards than standard office space. These cost more to maintain. But the high-cost environment also creates overcharge opportunities that appear regularly in MOB reconciliations: biohazard handling costs specific to one tenant billed building-wide, HVAC filtration upgrades triggered by one tenant's specialty passed to all tenants, insurance premium increases driven by high-risk occupants spread across lower-risk neighbors, and utility allocation errors that don't reflect actual metered consumption.
This guide explains the benchmark data, the structural cost drivers, and the four overcharge patterns that a forensic audit would check in any medical office building. More on that below.
Medical Office CAM Audit: A forensic review of the common area maintenance charges a medical practice paid under a MOB NNN lease, verifying that tenant-specific costs like biohazard disposal, specialty HVAC filtration, and surgery center insurance riders are not billed building-wide, and that utility allocation and property tax credits comply with lease terms.
Dental offices face a distinct version of these HVAC and utility overcharge patterns because dental equipment carries higher electrical load than general medical practices. Pharmacy tenants in medical office buildings encounter similar insurance allocation issues driven by controlled substance storage requirements. For the full picture of how NNN lease structures create hidden cost exposure in medical settings, see the medical office NNN lease traps guide.
Medical Office CAM Benchmarks
CAM charges in medical office buildings reflect both legitimate infrastructure costs and the pass-through practices of MOB landlords, who operate in a specialized market with limited tenant alternatives.
| Facility Type | CAM Range ($/SF/year) | Key Cost Drivers |
|---|---|---|
| On-campus hospital MOB | $17 – $24/SF | Full hospital infrastructure sharing, high insurance premiums |
| Off-campus Class A MOB | $14 – $20/SF | Specialized HVAC, backup power, cleaning |
| Off-campus Class B MOB | $10 – $16/SF | Older infrastructure, lower service levels |
| Suburban medical strip | $8 – $14/SF | Lower density, limited shared infrastructure |
| Dental / vision condo | $6 – $12/SF | Single-tenant or small multi-tenant structure |
Sources: CBRE Healthcare Real Estate Market Report (2024); JLL Medical Office Outlook (2024).
The gap between a Class A on-campus MOB ($20+/SF) and a typical Class A professional office building ($10–$14/SF) reflects the medical infrastructure premium. But it also reflects a market structure where MOB tenants, particularly small practices, have limited bargaining power and often sign landlord-form leases with broad pass-through provisions.
Here's what the data shows: CBRE's Healthcare Real Estate Market Report (2024) confirms that legitimate infrastructure costs account for roughly half of the CAM premium in Class A MOBs. The other half is where overcharges concentrate.
Why Medical Office CAM Costs More: Legitimate vs. Overcharged
Understanding which costs belong in MOB CAM and which are overcharges requires a framework for what medical buildings actually require.
Legitimate higher-cost items in MOB CAM:
- Enhanced HVAC filtration (HEPA or MERV-13+ filters required for clinical areas)
- Backup generator maintenance and testing
- Medical gas infrastructure (oxygen manifolds, vacuum lines in common corridors)
- Higher-frequency janitorial service with clinical-grade disinfectants
- Biohazard waste staging areas (the staging area itself, not disposal costs for specific tenants)
- Infection control protocols during common area renovations
- Higher property insurance premiums reflecting the building's medical use classification
Items that are overcharged when billed building-wide:
- HVAC filtration upgrades driven by one tenant's specialty (e.g., an oncology practice requiring HEPA filtration throughout its wing, with the cost passed to dermatology tenants three floors away)
- Medical waste disposal costs specific to one tenant's practice type
- Biohazard handling for clinical waste from a specific suite
- Personal protective equipment purchased for a specific tenant's building work
- Insurance premium increases caused specifically by a high-acuity tenant's specialty
Here's the thing: the distinction tracks the general rule in commercial real estate. Costs for shared infrastructure that benefits all tenants belong in CAM; costs specific to one tenant's operations belong to that tenant.
The Four Overcharge Patterns in Medical Office Buildings
1. Excluded Service Charges: Tenant-Specific Costs in the Shared Pool (Rule 2)
What happens: MOB leases typically list exclusions from the CAM pool, costs the landlord must absorb without pass-through. Standard exclusions include costs "attributable solely to the operations of a single tenant" and capital improvements. Medical office leases frequently include specific exclusions for "medical waste disposal" and "hazardous material handling" for individual tenant operations. The management fee overcharge guide covers how administrative overhead exclusions interact with the management fee cap in buildings like MOBs where overhead runs high.
Despite these exclusions, landlords sometimes consolidate all property-related costs from their accounting systems into the CAM pool without filtering tenant-specific items. A biohazard disposal invoice from a surgery center gets distributed across all tenants. An HVAC upgrade for one suite's specialized filtration requirements appears as a common maintenance line item.
Detection logic: Request the underlying vendor invoices for any line items related to HVAC, janitorial services billed at above-normal rates, specialized filtration, or waste handling. Compare each invoice against the lease's exclusion list. Any cost that the invoice identifies as related to a specific tenant's space or operations should not appear in the shared pool.
Dollar impact: A tenant-specific HVAC filtration system upgrade running $35,000–$80,000, passed through the shared pool at a 5% pro-rata share, adds $1,750–$4,000 to one tenant's bill. Multiplied across all non-responsible tenants in a 20-tenant building, the aggregate misbilling may equal the full cost of the upgrade.
Legal principle: Courts applying plain-language lease interpretation have required that each line item in an operating expense compilation be traceable to a service actually performed for the shared common area, not a specific tenant's suite. Costs attributable to a specific tenant's operations fall within the standard exclusion for "costs allocable solely to one tenant."
2. Insurance Overcharge: Premium Increases Driven by High-Risk Tenants (Rule 9)
What happens: Medical buildings carry higher property and general liability insurance than standard office buildings, reflecting the higher risk of operations involving medical equipment, medications, and clinical procedures. When a MOB adds a high-acuity specialty tenant, an orthopedic surgery center, a dialysis clinic, a cancer treatment facility, the building's insurance premiums typically increase.
The overcharge occurs when landlords pass that premium increase building-wide without accounting for the fact that it was caused by one tenant's operations. A psychiatric practice, a dermatology office, and a primary care group all pay increased premiums that reflect the risk profile of the surgery center on the first floor.
When it's recoverable: Most MOB leases permit insurance premium pass-throughs but limit them to premiums for coverage types listed in the lease (typically building property insurance, general liability, and sometimes umbrella coverage). Premium increases for coverage types not listed, or for policy riders added because of a specific tenant's operations, may fall outside the permitted pass-through scope.
Detection logic: Obtain the property's insurance declarations page for the base year and current year. Identify any new policy riders, increased coverage limits, or new coverage categories. Cross-reference against the lease's permitted insurance pass-through categories. For a systematic approach to identifying impermissible coverage types, see the insurance overcharge section of the what is a CAM audit guide.
Dollar impact: Commercial property insurance premiums increased 16.9% in 2023 (Marsh Global Insurance Market Index, Q4 2023) and an additional 8.2% in 2024. A building where premiums increased above the national trend may have tenant-specific risk factors driving excess increases. On a $200,000 annual premium that increased 25% above baseline (15% driven by a surgery center's risk profile), the surgery center's operations add $30,000 building-wide, or $1,500–$3,000 per year to each smaller tenant's bill.
Legal principle: Courts have held that the pass-through of insurance premiums is governed by the lease provisions defining what insurance costs are recoverable. Increases attributable to a specific tenant's operations are not recoverable from other tenants under a standard pass-through provision that does not authorize specialty risk riders driven by one occupant's use classification.
3. Tax Overallocation: Assessment Changes Billed Without Adjustment (Rule 10)
What happens: Medical office buildings often sit on parcels that are re-assessed separately from the surrounding market when significant capital investment occurs, a tenant build-out, a facility expansion, or a major equipment installation. When that reassessment results in a higher tax bill, the landlord passes the increase through CAM.
The overallocation occurs in two scenarios:
Scenario A, Assessment driven by one tenant's improvement: A surgery center tenant builds out a specialized facility worth $2 million in tenant improvements. The assessor notes the improvement and increases the parcel's assessed value. The resulting tax increase is passed building-wide. Other tenants pay for the surgery center's improvement.
Scenario B, Tax appeal credit not passed through: If the landlord successfully appeals the property's tax assessment and receives a refund or credit, that benefit should flow back to tenants who paid the higher amount. When landlords receive refunds without crediting tenant reconciliations, tenants pay the original over-assessed amount permanently.
Detection logic: Obtain the property tax bills and any assessment change notices. For Scenario A, determine whether the assessment change was triggered by a specific tenant's improvement. For Scenario B, check whether assessment appeal outcomes were disclosed in reconciliation statements and whether credits were applied.
Dollar impact: Property tax appeals in medical markets frequently produce 10–20% reductions in assessed value. On a $400,000 annual tax bill, a 15% reduction represents $60,000, divided among 15 tenants, roughly $4,000 each. If that $60,000 credit was not passed through to tenants, each tenant has a recoverable credit claim for each uncredited year.
4. Utility Overcharge: Unmetered Allocation vs. Actual Consumption (Rule 11)
What happens: Medical tenants use significantly more utilities than standard office tenants. A radiology suite with MRI and CT equipment running continuously, an oncology infusion center with temperature-controlled medication storage, or a clinical laboratory with specialized equipment all consume electricity at rates far above a general medical practice.
The overcharge occurs when landlords allocate utility costs by square footage (pro-rata) rather than by metered consumption. A 3,000 SF general practice pays the same utility rate per square foot as a 3,000 SF MRI suite, even though the MRI suite consumes five to ten times more electricity.
If your lease specifies pro-rata utility allocation, square-footage-based billing is contractually authorized even if it results in cross-subsidy. The claim arises when the lease requires metered or consumption-based allocation but the landlord applies pro-rata instead.
Detection logic: Review the utility allocation provision in your lease. If it requires metering or consumption-based allocation, compare the landlord's method against that requirement. If submeters exist in the building, the landlord should be using submeter data. If the lease requires submetering but the landlord applies pro-rata allocation, that's a Rule 11 overcharge.
Dollar impact: For a 3,000 SF general practice in a building where utilities run $4/SF annually under pro-rata allocation, the annual utility portion of CAM is $12,000. If the practice's actual consumption is $3/SF (below average, due to no specialized equipment), the overcharge is $3,000/year, or $15,000 over a 5-year lookback.
Worked Example: 4,000 SF Primary Care Practice
Assume a primary care practice in a 60,000 SF Class A off-campus MOB. Lease terms: NNN structure, 6.67% pro-rata share, annual CAM cap of 7% on controllable expenses. Building has: a surgery center (8,000 SF), five general medical practices, two dental offices, and a physical therapy suite.
Reconciliation review for 2025:
| Finding | Billed to Tenant | Should Be | Annual Overcharge |
|---|---|---|---|
| HVAC filtration upgrade (surgery center wing only) | $5,340 (6.67% × $80,000) | $0 (tenant-specific exclusion) | $5,340 |
| Insurance premium increase (surgery center risk rider) | $2,668 (6.67% × $40,000 rider) | $0 (not in permitted categories) | $2,668 |
| Utility allocation (pro-rata vs. submeter requirement) | $3,202 | $2,001 (submeter actual) | $1,201 |
| Tax increase from surgery center TI assessment | $1,600 (6.67% × $24,000 increase) | $0 (improvement-driven) | $1,600 |
| Total annual overcharge | $10,809 |
At a 5-year lookback, that's $54,045 in recoverable overcharges, before interest.
Run a free audit on your medical office CAM charges, the analysis identifies each overcharge type and quantifies the dollar impact automatically. Once findings are confirmed, use the CAM dispute letter template to send a written claim with the specific calculations and lease citations that produce a response.
"In MOBs, the overcharge is almost always structural, not clerical. A surgery center joins the building, insurance premiums jump, and every other practice absorbs the increase without understanding why. CAMAudit's Rule 9 detects insurance premium jumps above market baseline and flags them for investigation. That is the starting point for a $50,000 recovery." —
CAMAudit vs. Traditional Medical Office Audit
For a 4,000 SF primary care practice:
| Approach | Cost | Turnaround | Tenant Net Recovery |
|---|---|---|---|
| Healthcare real estate attorney (hourly) | $5,000–$15,000 | 4–8 weeks | Variable |
| Lease audit firm (+ 33% contingency) | $1,500 + $3,567 | 3–5 weeks | $7,242 net |
| CAMAudit (flat fee) | $79 | Under 15 minutes | $10,610 net |
For smaller medical practices, traditional audit economics often don't make sense, the audit cost approaches the expected recovery. CAMAudit's flat fee changes that calculus: the analysis costs $79 regardless of whether the overcharge is $5,000 or $50,000.
Legal Principles in Medical Office CAM Disputes
Exclusion Clause Enforcement
Courts evaluating MOB CAM disputes perform a line-item analysis requiring each vendor invoice to be traced to the services performed and evaluated against the lease's exclusion language. When costs are "attributable solely to the operations of a single tenant," they fall within the standard exclusion regardless of how the landlord's GL coded them. The analysis is invoice-level, not category-level.
Insurance Premium Allocation
Courts have held that insurance premium pass-throughs are governed by the specific categories of coverage listed in the lease. Increases attributable to a specific tenant's risk profile, particularly specialty riders added for surgical facilities or high-acuity occupants, are not recoverable from other tenants under standard property insurance pass-through language that does not enumerate specialty medical risk coverage.
Utility Allocation Methodology
When a lease specifies consumption-based or metered utility allocation and the landlord applies square-footage pro-rata instead, courts have ordered recalculation using actual meter readings for all open reconciliation periods. The contractual allocation methodology controls, and the landlord's administrative preference for pro-rata allocation does not override explicit lease language requiring metered billing.
Lease Language Risks in Medical Office Buildings
Risk 1: Broad HVAC Pass-Through Without Use Restriction
Many MOB leases pass through "HVAC system maintenance and repair" without specifying whether that covers only shared system components or also tenant-specific mechanical equipment. A landlord who replaces filtration systems in one tenant's wing can argue the cost is "HVAC maintenance" rather than a tenant-specific improvement.
What to look for: Any HVAC pass-through provision that does not distinguish between shared infrastructure (air handlers serving multiple suites) and dedicated equipment (standalone units serving one tenant). The more specific the lease is about what constitutes "common area" HVAC, the less interpretive room the landlord has.
Risk 2: Insurance Pass-Through Without Coverage-Type List
Standard office leases list the specific types of insurance whose premiums can be passed through. Generic language like "all property insurance" or "building insurance" is broad enough to include riders and coverage categories added for specialized tenants. If the lease doesn't limit the pass-through to named coverage types, the landlord has significant room to pass through specialized coverage costs.
What to look for: Compare the insurance pass-through provision against the actual policy declarations page. Identify any policy riders that were not in the building's coverage at lease execution. Challenge pass-throughs for coverage types not listed in the lease.
Risk 3: Undefined "Medical Waste" in Exclusion Schedule
The exclusion schedule's medical waste provision should clearly define what constitutes tenant-specific waste handling versus shared facility waste costs. "Biohazard disposal" is ambiguous, it could refer to the staging area for all tenants (a shared cost) or the disposal cost for a specific tenant's regulated medical waste (a tenant cost). If the distinction isn't drawn in the lease, expect disputes.
Medical Office CAM: Common Questions
Why do medical office buildings charge so much more in CAM than regular office buildings?
Legitimate reasons include higher-grade HVAC filtration, backup power infrastructure, enhanced janitorial standards, and higher insurance premiums reflecting medical use classification. The premium over standard office CAM is real and documented. The question for any individual tenant is whether the specific costs in their reconciliation reflect genuine medical-infrastructure overhead or whether tenant-specific expenses are being spread building-wide.
Is HVAC filtration always a shared expense in a MOB?
Not necessarily. If the enhanced filtration serves only one tenant's space, it's a tenant-specific cost. If it serves shared corridors, lobbies, or mechanical rooms that all tenants use, it may be a legitimate shared expense. The location of the filtration system, which air handlers it connects to, which zones it serves, is the factual question. A vendor invoice identifying the installation location is the key document.
Can I request the building's insurance declarations page?
Yes. Most commercial audit rights clauses entitle tenants to examine the records supporting CAM charges, which includes insurance policies and premium documentation. Send a written audit request citing the specific provision in your lease. The landlord must produce the declarations page for any year whose premiums appear in the reconciliation.
What happens if a radiology tenant's equipment causes structural damage affecting CAM costs?
Costs to repair damage caused by a specific tenant's operations are typically that tenant's responsibility under their lease and the landlord's insurance claim process, not a shared CAM cost. If such costs appear in a CAM reconciliation, they should be challenged as a Rule 2 exclusion violation, costs attributable solely to one tenant's operations.
Are utility costs a major overcharge source for medical practices without specialized equipment?
Yes, particularly for practices in buildings with high-consumption specialty tenants. Square-footage pro-rata allocation systematically undercharges high-consumption tenants and overcharges low-consumption practices when electricity usage is highly uneven. If your lease requires consumption-based allocation or if submeters exist, insist on metered billing. If your lease only permits pro-rata, the cross-subsidy is contractually authorized even if economically unfair.
How does the SOL work for medical office CAM disputes?
The statute of limitations depends on state. For major medical markets: California, 4 years (CCP § 337); Texas, 4 years; New York, 6 years; Illinois, 10 years. States following the discovery rule may toll the SOL from the date you first discover the overcharge rather than from the reconciliation date, meaning a practice that has never audited may still have claims going back to lease inception. See CAM reconciliation deadlines for the full state-by-state analysis.
Related Resources
- Medical Office NNN Lease Traps: HVAC, Biohazard, and Insurance Overcharges
- Insurance CAM Passthrough: What's Recoverable and What Isn't
- Utility Double-Billing in CAM: How Tenants Get Charged Twice
- Excluded Services in CAM Charges
- Property Tax CAM Passthrough: What Tenants Should Audit
- CAM Dispute Guide
- CAM Overcharge Detection Playbook
- Tenant CAM Audit Guide: step-by-step audit methodology for medical office and all other property types
Sources
- CBRE Research, Medical Office and Healthcare Property Data (2024)
- JLL, Medical Office Outlook (2024)
- BOMA International, Experience Exchange Report (2023)
- Tango Analytics, CAM Reconciliation Error Analysis (2023)
- IREM, Operating Expense Resources (2024)
Frequently Asked Questions
Why do medical office buildings charge so much more in CAM than regular office buildings?
Legitimate reasons include higher-grade HVAC filtration (HEPA or MERV-13+ for clinical areas), backup generator maintenance, enhanced janitorial standards, and higher property insurance premiums reflecting medical use classification. Class A medical office CAM runs $15 to $22 per SF versus $10 to $14 per SF for standard Class A office. The premium is real, but it creates overcharge opportunities when tenant-specific costs get spread building-wide.
Can a surgery center's high-risk operations affect my insurance costs?
Yes, and this is a documented overcharge pattern. When a MOB adds a high-acuity specialty tenant, building insurance premiums typically increase. Landlords sometimes pass that premium increase building-wide without accounting for the fact that it was driven by one tenant's operations. A general practice pays increased premiums reflecting the surgery center's risk profile. Coverage riders added for one tenant's operations may not be within your lease's authorized pass-through categories.
What HVAC costs are legitimate shared expenses in a medical office building?
Costs for shared central plant equipment and systems serving two or more tenant suites are legitimate shared expenses. Filtration upgrades required by one tenant's specialty, rooftop units serving only one suite, and dedicated mechanical equipment for a single tenant are tenant-specific costs that should not appear in the shared pool. The location of the equipment and which spaces it serves determines classification.
How does utility billing work for medical practices without specialized equipment?
The overcharge occurs when landlords allocate utilities by square footage (pro-rata) rather than by metered consumption. A general practice pays the same rate per SF as an MRI suite even though the MRI suite consumes five to ten times more electricity. If your lease requires metered or consumption-based allocation but the landlord applies pro-rata instead, the difference is a Rule 11 overcharge.
What is the statute of limitations for medical office CAM disputes?
It varies by state. For major medical markets: California, 4 years (CCP § 337); Texas, 4 years; New York, 6 years; Illinois, 10 years. States following the discovery rule may toll the SOL from the date you first discover the overcharge rather than from the reconciliation date. A practice that has never audited may still have claims going back to lease inception under the discovery rule.
CAMAudit is a document analysis and automation tool. The analysis described on this page does not constitute legal advice. Consult a licensed attorney before sending any legal correspondence to your landlord.