## Facts

- After an industrial tract in Chicago was divided, Cavalea purchased certain parcels and Burns Philp purchased the remainder.
- Due to an error in tax records, from 1987 to 1993 Burns Philp paid real estate taxes assessed on two parcels owned by Cavalea, totaling about $125,000.
- Burns Philp discovered the mistake in mid-1993, demanded reimbursement, and Cavalea refused.
- Relying on an inaccurate survey, Burns Philp built a 205-foot fence that encroached onto Cavalea’s land, effectively occupying about 2,000 square feet.
- Cavalea later learned of the encroachment from a subsequent survey and filed a counterclaim in 1995 seeking trespass damages and injunctive relief; Burns Philp first learned of the encroachment when served.
- The fence was removed in 1996.
- Burns Philp also alleged diesel fuel contamination migrating from Cavalea’s property due to Cavalea’s use of a tanker-trailer as a refueling station without spill containment; the district court found Burns Philp’s proof of damage inadequate.

## Issues

1. Whether an Illinois unjust-enrichment/restitution claim for mistakenly paid real estate taxes is governed by the five-year limitations period in 735 ILCS 5/13-205.
2. Whether the claim could avoid that limitations period by characterizing restitution as purely equitable or by using a later accrual date based on discovery of the mistake.
3. Whether a landowner may recover trespass damages for an encroaching fence without first giving the encroacher notice or demand to remove it.
4. Whether dismissal of the diesel-fuel contamination claim was proper where the trial court found the expert proof insufficient to establish compensable harm.

## Decision

- The court held that Illinois treats unjust-enrichment claims as actions at law subject to the five-year statute of limitations in 735 ILCS 5/13-205.
- The restitution award was modified to limit recovery to tax payments made within five years before suit.
- The court rejected attempts to avoid the limitations bar by labeling the claim “equitable” or by applying a discovery-based accrual in these circumstances.
- The court reversed the denial of Cavalea’s trespass damages claim, holding that Illinois trespass liability does not require prior notice to the trespasser.
- The court affirmed dismissal of Burns Philp’s contamination claim because the evidence, including expert proof, did not reliably establish damages.

## Legal Principles

- Under Illinois law, unjust enrichment is treated as an action at law and is governed by the five-year limitations period for actions on unwritten contracts and residual civil actions. 735 ILCS 5/13-205.
- Restitution is not categorically an equitable remedy; whether it is treated as legal or equitable depends on the governing substantive law and the relief sought.
- A party that repeatedly pays charges without inquiry may be unable to postpone accrual of a claim through a discovery-based theory where the error was readily discoverable through ordinary diligence.
- Trespass is a strict-liability tort under Illinois law; unauthorized physical intrusion onto another’s land supports damages without a prerequisite of prior notice or demand.
- Claims for environmental contamination damages require proof of actual harm and a reliable evidentiary basis; weak or incomplete expert methodology can justify judgment against the claimant after trial.

## Conclusion

The Seventh Circuit applied Illinois’s five-year limitations period to restrict recovery for mistakenly paid real estate taxes, held that trespass damages may be recovered for encroachment without prior notice, and affirmed judgment rejecting the claimed diesel-fuel contamination damages for lack of reliable proof.


Burns Philp Food, Inc. v. Cavalea Cont'l Freight, Inc., 135 F.3d 526 (7th Cir. 1998)