Illinois CAM Disputes: The 10-Year Recovery Window [2026]
TL;DR: Illinois gives commercial tenants more time to recover CAM overcharges than any other state: 10 years under 735 ILCS 5/13-206. In our worked example, a Chicago office tenant recovered $49,650 over five years from a base year gross-up failure, with full 10-year potential exceeding $100,000.
Illinois CAM audit window: Under 735 ILCS 5/13-206, Illinois commercial tenants have 10 years from when each CAM overcharge accrued to bring a breach of written contract claim. No statutory CAM audit right exists, but the discovery rule may extend the window further.
40% of commercial CAM reconciliations contain material billing errors (Tango Analytics, 2023)
Illinois gives commercial tenants more time to recover CAM overcharges than any other state in the country. Ten years. Under 735 ILCS 5/13-206 for written contract claims, your commercial lease is a written contract. Most tenants assume the window is three or four years, because that is what they have heard, or because their attorney in another state told them that. In Illinois, that assumption costs money.
If you need the full operating playbook, go to the CAM dispute guide. To see the evidence package before you upload, review the sample report.
"Illinois gives tenants the longest CAM recovery window in the country at 10 years. I built CAMAudit to take advantage of that depth, catching patterns across a decade of reconciliation statements that shorter windows would miss." — Angel Campa, Founder of CAMAudit
Why the 10-year window matters in practice
CAM overcharges are rarely caught in the first year. Management fee creep past the lease cap happens in year two. Base year gross-up errors compound quietly through years three and four. By the time a tenant suspects something is wrong, often because they hired a new CFO or switched property managers and someone finally looked at the reconciliations, they may be in year six or seven of the lease. In California or Texas, that tenant has lost the early years. In Illinois, they have not.
735 ILCS 5/13-206: the 10-year written contract SOL
Illinois law provides a 10-year limitation period for actions on written contracts. The full citation is 735 ILCS 5/13-206.
A common mistake: 735 ILCS 5/13-205 provides a five-year period for "all civil actions not otherwise provided for." If someone reads only that provision and stops there, they get the wrong answer for written contracts. Your commercial lease is a written contract, and 735 ILCS 5/13-206 gives you 10 years.
Comparison of Illinois SOL provisions:
| Statute | Period | Applies to |
|---|---|---|
| 735 ILCS 5/13-206 | 10 years | Written contracts |
| 735 ILCS 5/13-205 | 5 years | Unwritten contracts, other civil actions |
| 735 ILCS 5/13-202 | 2 years | Personal injury, certain tort claims |
If someone tells you your CAM claim is subject to a five-year limit in Illinois, ask them whether they are applying 13-205 to a written contract. Section 13-206 controls for written agreements.
What the 10-year window means in dollars
Recovery difference between Illinois and a four-year SOL state on the same overcharge:
A tenant in a 2,000 SF Chicago retail space pays $10 per SF in CAM annually ($20,000/year). Landlord applies a systematic 5 percent overcharge through management fee stacking, where a property management fee and a separate asset management fee each pass through when the lease only permits one. Combined cap is 5 percent of CAM; the landlord bills 7.8 percent. That 2.8 percent excess on a $260,000 CAM pool means the tenant's share of the excess is approximately $1,000 per year.
| Recovery window | Years recovered | Total recovery |
|---|---|---|
| 4-year SOL (CA, TX) | 4 | $4,000 |
| 5-year SOL (FL, GA, NJ) | 5 | $5,000 |
| 6-year SOL (NY) | 6 | $6,000 |
| 10-year SOL (IL) | 10 | $10,000 |
Same lease. Same error. Same tenant. Illinois is worth 2.5 times the four-year SOL states on this error alone.
Scale to a larger tenant: a 5,000 SF Chicago office tenant paying $11 per SF in CAM ($55,000 per year) with a base year error generating $8,000 per year in excess billings:
| Recovery window | Total recovery |
|---|---|
| 4-year SOL | $32,000 |
| 5-year SOL | $40,000 |
| 10-year SOL (IL) | $80,000 |
In this example, the building was at 55 percent occupancy in 2019, which the landlord used as the base year. Under a properly functioning gross-up clause, the landlord should have normalized base year expenses to a 95 percent occupancy equivalent before establishing the baseline. Because they did not, every subsequent year's escalation is measured against an understated base. CAMAudit detects this under Rule 7 (Base Year Error).
Base year gross-up issue in Chicago commercial real estate
Chicago's office market had a significant occupancy disruption in 2019 through 2021. Many leases executed in that window used 2020 or 2021 as base years, when buildings were operating at 40 to 60 percent of normal occupancy. Expenses that scale with occupancy (HVAC, janitorial, utilities) were correspondingly low. Landlords who did not gross up these base year expenses to a normalized 95 percent occupancy equivalent built in an overcharge that compounds every year.
Suppose base year janitorial was $180,000 in 2020 (at 50% occupancy). Normalized, it should have been approximately $340,000. Annual escalation is measured against $180,000 instead of $340,000. By year five, on a 3 percent annual increase, the excess annual billing is $20,000 or more for a mid-size tenant. Over 10 years in Illinois, that is $200,000 in recoverable overcharges.
Account stated doctrine: why you must object annually
Illinois recognizes the account stated doctrine in commercial contexts. If a creditor (your landlord) renders a statement of account and the debtor (you) pays it without objection, the payment can be treated as acceptance of the account as stated. Landlords raise this defense when tenants bring CAM claims years after paying reconciliations without protest.
Account stated does not automatically defeat a 10-year claim. But it creates a factual argument that consistent payment without objection constitutes acquiescence to the amount charged. Illinois courts have allowed account stated arguments in commercial contexts where there was a course of dealing involving regular statements and payments.
Strategic response: document your objection in writing every year, even if you are not yet prepared to file a formal dispute. A written objection sent by certified mail prevents the account stated defense from attaching to that year's charges. A letter stating "We are reviewing the 2024 CAM reconciliation and reserve all rights to dispute any charges upon completion of our review" is enough to interrupt the argument for that year.
Discovery rule: potential extension beyond 10 years
Illinois applies the discovery rule to some contract claims. Under this doctrine, the statute of limitations does not begin to run until the plaintiff knew or should have known that a cause of action existed.
If the overcharge is apparent from the reconciliation statement itself (such as a management fee plainly above the lease's stated cap), the SOL likely runs from delivery of that statement.
But if the overcharge requires access to information the tenant does not have, for example the landlord's total CAM pool that is not disclosed on the statement or a pro-rata calculation error that depends on knowing the total building GLA, Illinois courts have sometimes held that the discovery rule tolls the SOL until the tenant had access to the underlying data. Not a guaranteed extension, and it depends heavily on what information was disclosed and when, but it is a recognized argument under Illinois law.
Illinois-specific considerations for dispute strategy
Illinois has no commercial tenant anti-retaliation statute. Challenging your CAM reconciliation does not trigger any statutory protection if the landlord decides to become difficult. Use collaborative or neutral dispute letter draft tone unless the lease relationship is already adversarial.
Chicago courts apply plain contract interpretation and are experienced with commercial lease disputes. ICSC and BOMA lease forms are common in the market, and courts enforce clear lease exclusion language as written. If your lease says management fees cannot exceed 4 percent of gross revenues, a fee that exceeds that cap is a breach, and an Illinois court will say so. Independent covenant principles apply, so tenants cannot withhold rent during a CAM cap dispute.
For large multi-tenant buildings in Chicago managed by institutional landlords like CBRE, JLL, or Cushman & Wakefield, the pro-rata share denominator issue is particularly common. CAMAudit detects Rule 4 (Pro-Rata Share Error) by comparing the stated GLA denominator in the reconciliation to the actual total GLA including all premises, anchors, and excluded spaces. In Chicago's large Class A towers and mixed-use developments along the Loop and West Loop, this calculation is frequently wrong in the landlord's favor. Similar patterns show up in suburban markets across Detroit, Minneapolis, and Columbus.
Worked Example: Chicago Office Tenant, Base Year Gross-Up Failure
Setup: 5,000 SF office tenant in a 200,000 SF building in Chicago's West Loop. Lease executed January 2021, base year 2020. CAM per SF capped at 5 percent annual increase over prior year. Building was at 52 percent occupancy in 2020.
Error: 2020 base year expenses were not grossed up to 95 percent occupancy. Actual 2020 expenses: $1,600,000. Normalized to 95 percent occupancy: $2,880,000 (using a linear scaling for occupancy-variable costs; approximately 70 percent of the expense pool scales with occupancy).
Effect on tenant:
| Year | Actual CAM billed (per SF) | Correct CAM (per SF) | Annual excess |
|---|---|---|---|
| 2021 | $9.20 | $7.40 | $9,000 |
| 2022 | $9.66 | $7.77 | $9,450 |
| 2023 | $10.14 | $8.16 | $9,900 |
| 2024 | $10.65 | $8.57 | $10,400 |
| 2025 | $11.18 | $9.00 | $10,900 |
| 5-year total | $49,650 |
Under the Illinois 10-year SOL, the tenant can recover errors going back to 2021 through 2031. Full 10-year recovery, assuming the error persists, could reach $100,000 or more. In a four-year SOL state, the same tenant would be limited to approximately $40,000.
CAMAudit flags this under Rule 7 by computing what base year expenses should have been at normalized occupancy and comparing the escalation trajectory.
Comparing Illinois to Other States
| State | SOL (Written Contracts) | Statutory CAM Audit Rights | Key Statute |
|---|---|---|---|
| Illinois | 10 years | None (contract law) | 735 ILCS 5/13-206 |
| Michigan | 6 years | None (contract law) | MCL § 600.5807(8) |
| Ohio | 6 years | None (contract law) | ORC § 2305.06 |
| Minnesota | 6 years | None (contract law) | Minn. Stat. § 541.05 |
| California | 4 years | Yes (SB 1103 for QCTs) | Cal. Civ. Code § 1950.9 |
Related state guides:
Illinois SOL and key statutes reference
| Item | Detail |
|---|---|
| Written contract SOL | 10 years (735 ILCS 5/13-206) |
| Oral/unwritten contract SOL | 5 years (735 ILCS 5/13-205) |
| Specific commercial CAM statute | None |
| Discovery rule | Recognized; applies to some contract claims |
| Account stated doctrine | Recognized; object in writing annually |
| Commercial tenant anti-retaliation | None |
| Rent withholding during dispute | Generally not permitted |
| Lease-defined dispute windows | Enforced by IL courts |
Frequently Asked Questions
Frequently Asked Questions
How long do Illinois commercial tenants have to recover CAM overcharges?
Illinois provides a 10-year statute of limitations for written contract claims under 735 ILCS 5/13-206. Your commercial lease is a written contract, and a CAM overcharge is a breach of that contract. Compared to 4 years in California and Texas, and 6 years in New York, Illinois offers the longest recovery window of any major commercial real estate state.
Does my lease's 90-day dispute window override Illinois's 10-year statute of limitations?
Yes, and this is critical. The 10-year SOL sets the outer legal limit, but it does not override a contractual condition precedent requiring you to object within 90 days. Illinois courts generally enforce those lease-defined windows. You must satisfy both deadlines to preserve a viable claim: the contractual window for the current year and the statutory period for earlier years.
What is the account stated doctrine and how does it affect Illinois CAM claims?
Landlords raise this defense when a tenant has consistently paid reconciliation statements over many years without objecting. Illinois courts have allowed it in commercial contexts. Send a written annual objection or reservation of rights each year, even before reviewing the reconciliation in detail. A one-paragraph letter by certified mail is sufficient to prevent the defense from attaching.
Can I use the discovery rule to extend my Illinois CAM claim beyond 10 years?
Potentially, in specific circumstances. If the overcharge required access to information the landlord did not disclose, such as the actual CAM pool denominator, there is an argument the SOL tolled until you received that information through an audit request. Fact-specific and requires Illinois attorney review before relying on it as a planning tool.
Why is Chicago's post-pandemic office market particularly exposed to base year gross-up errors?
Many leases executed between 2020 and 2022 used a pandemic-period year as the base year, when buildings were at 40 to 60 percent occupancy. Landlords who did not gross up those base year expenses to a normalized 95 percent occupancy equivalent built in a structural overcharge that compounds every year. Over 10 years in Illinois, the cumulative impact can exceed $100,000 for a mid-size tenant.
Legal Disclaimer: This article provides general educational information about Illinois commercial lease law and CAM dispute rights. Statute of limitations, discovery rules, and lease enforcement vary by specific facts and jurisdiction. Consult a licensed Illinois attorney for advice specific to your situation.
Related reading:
- CAM Recovery Guide: How commercial tenants recover CAM overcharges, with step-by-step process and state lookback windows
- Base Year Error: How an Understated Gross-Up Costs Tenants Thousands
- Management Fee Overcharge in CAM
- Pro-Rata Share Errors
- CAM Audit Cost: Big Four vs. Boutique vs. AI
- Understanding CAM Dispute Rights, multi-state dispute guide