Illinois UST disclosure exam guide
Illinois underground storage tank disclosure
A seller knows there is an old heating-oil tank under the yard. The tank may fall outside the regulated UST definition, but that does not answer the seller-report question. Keep three questions separate: what the seller knows, what the tank rules require and what the cleanup records establish.
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The short answer
For a sale covered by the Illinois Residential Real Property Disclosure Act, item 21 asks about the seller's awareness of underground fuel storage tanks. A qualifying home heating-oil tank can be excluded from the regulatory UST definition and still require a truthful yes answer on that report. For a regulated UST, the new owner reports an ownership change to OSFM within 30 days after acquisition. Registration, removal, a reported release and a No Further Remediation letter are separate facts. None should be presented as a blanket clean-property guarantee.
Reviewed October 24, 2026. Underground storage tanks appear at Illinois IV.E.4 in the June 24, 2026 PSI broker outline. The whole Disclosures area accounts for 10 of 40 scored state questions; this page has no separate question allocation. It covers exam distinctions and selected Illinois requirements, not every tank classification or a cleanup plan for a particular site.
Read the disclosure, tank and cleanup files separately
- Start with the seller report. For a covered transaction, Section 77/20 requires delivery before contract signing. Item 21 concerns known underground fuel tanks, not just tanks registered with OSFM. The seller supplies the actual-knowledge answer and an explanation for a yes or not-applicable response. A broker should not invent an answer for the seller.
- Apply the regulatory definition separately. Section 174.100 generally covers systems holding regulated substances when at least 10% of system volume, including connected underground piping, is below ground. Then check the exclusions. Farm or residential motor-fuel tanks of 1,100 gallons or less for noncommercial use and heating-oil tanks of any capacity used exclusively for consumptive heating on a farm or residence are examples. These are different exclusions with different conditions.
- Check location and partial exclusions. Septic tanks and tanks of 110 gallons or less are excluded from the UST definition. A tank in a basement or vault has a specific floor-location and visibility test; below street level alone does not decide it. Partial exclusions are different: the listed systems can retain release-reporting, response, corrective-action and financial-responsibility requirements. Use the full rule for an unfamiliar system. The visibility condition includes all sides, top and base, with the tank on or above the floor or ground specified by the rule. An exclusion from this definition does not settle other environmental or disclosure laws.
- Put ownership changes on the right clock. Section 176.440(g) gives the subsequent regulated-UST owner 30 days after acquisition to report the change electronically to OSFM, with the Authorization to Submit, property PIN and ownership evidence. This is separate from the covered home seller's precontract report and from the notice a seller of new or recertified tank equipment must give under subsection (h).
- Respond to suspected releases. Section 176.300 assigns immediate IEMA reporting to regulated owners or operators for its listed evidence, operating conditions and monitoring results, subject to stated exceptions. It also requires an immediate 911 call when a suspected release presents a hazard to life. A closing date or pending final laboratory report is not a reason to ignore an already-triggered duty.
- Follow the incident through cleanup. Illinois EPA oversees corrective action after a UST release is reported to IEMA. Tank removal and site assessment do not, by themselves, establish that an incident is closed. Read the incident history, technical reports, agency correspondence and any NFR letter together. An owner or operator's regulated site assessment is different from a buyer's broader environmental due diligence; the assessment's scope and findings must be read.
- Read the limits of the NFR letter. In the LUST program, it signifies that no further corrective action is required for the release under the applicable program requirements. Its scope, land-use assumptions, recording and controls matter. A commercial-use restriction cannot be treated as approval for unrestricted housing, and conditions that support the letter must continue to be observed.
- Keep brokerage work within its authority. Communicate known facts accurately, retain the relevant documents and involve the sponsoring broker. A seller's broker has a separate Section 15-25 duty to timely disclose actually known latent material adverse physical facts to prospective buyer customers when those facts would not be found by a reasonably diligent inspection. Classification, sampling, regulated tank work and legal liability need the appropriate specialists.
| Document or event | What it addresses | What remains to check |
|---|---|---|
| Seller report item 21 | Seller awareness of underground fuel tanks | Regulatory status, condition and any release |
| Section 174.100 analysis | Defined UST system and applicable exclusions | Other disclosure duties and the specific requirements that remain |
| OSFM registration or ownership filing | Tank/facility information and reported ownership | Accuracy, compliance history and separate release records |
| Removal and assessment records | Work performed and findings within the assessment scope | Open corrective action and other environmental conditions |
| Illinois EPA incident file | Reported release and corrective-action history | Current status, outstanding requirements and relevant correspondence |
| NFR letter | Program closure under its terms | Scope, controls, recording and compatibility with planned use |
| Fund eligibility determination | OSFM determination under the funding rules | Eligible costs, deductible, approved plans and payment conditions |
The distinctions that matter
| Distinction | How it works | What to notice |
|---|---|---|
| Underground fuel tank vs. regulated UST | The seller report asks about actual awareness of a physical feature. The regulatory definition adds substance, system-volume and exclusion tests. | A regulatory exclusion does not erase seller knowledge. |
| Motor fuel vs. heating oil | The cited small farm/residential motor-fuel exclusion has a 1,100-gallon cap and noncommercial-use condition. The separate farm/residential consumptive heating-oil exclusion is not limited to that capacity. | Identify the product and use before applying a capacity number. |
| Full exclusion vs. partial exclusion | A system outside the defined UST category differs from a listed system exempt from only some requirements. Partial exclusion does not mean every reporting or response duty disappears. | Read what remains applicable. |
| Tank registration vs. release history | OSFM tank and facility records are different from Illinois EPA incident and corrective-action records. An active registration is not a finding that no contamination exists. | Ask which file answers the question. |
| Out of service vs. removed | An inactive tank may remain in place. Removal addresses physical equipment. Neither label alone establishes the absence of a release or completion of corrective action. | Equipment status is not cleanup status. |
| NFR letter vs. unrestricted-use warranty | The letter has a program, incident and conditions. Read its actual land-use and control provisions before describing what it permits. | No further action within the letter's scope is not clean forever. |
| Seller disclosure vs. buyer investigation | Actual knowledge governs the seller report. The buyer's assessment of environmental and contract risk can require different records and qualified advice. | No special seller inquiry is not a substitute for due diligence. |
Work through the facts
An excluded home tank is still a known fuel tank
In a covered Illinois home sale, the seller knows an intact buried tank was used exclusively for the home's heating oil. No leak is known. The seller wants to answer no because the tank is excluded from the UST definition.
- The question supplies the residential heating-use facts for the regulatory exclusion.
- The report asks about awareness of an underground fuel tank, not just a known leak or a registered facility.
- The facts say the tank remains present. A previously removed tank and an unresolved release require a different, fact-specific disclosure analysis.
Answer: Answer yes and explain the known tank. Do not claim a leak exists without evidence.
Use total system volume
Assume a system stores a regulated substance and no exclusion applies. Its total tank-and-connected-piping volume is 1,200 gallons, with 150 gallons of that volume below ground.
- 150 / 1,200 = 0.125, or 12.5%.
- The calculation uses system volume, not how many gallons of fuel happen to be in the tank that day.
Answer: The stated system meets the at-least-10% element. The assumed substance and exclusion facts still matter.
A change of owner is not an annual update
A buyer acquires a registered UST facility and decides to leave the former owner in the OSFM records until year end.
- Section 176.440(g) treats ownership as a reportable information change.
- The subsequent owner's clock is 30 days after acquisition, not the next annual business review.
Answer: Complete the required ownership-change notification within 30 days.
An investigated alarm has specific exception conditions
A release-detection device is found defective, is immediately repaired and additional monitoring does not confirm the initial result. No other release evidence is present.
- Section 176.300(a)(3)(A) describes this combination of facts as an exception to that monitoring-results reporting trigger.
- A mere assumption that an alarm is faulty would not supply those facts.
Answer: Apply the stated exception to that trigger. Do not turn it into permission to ignore other evidence.
Removal is not the end of an open incident
The seller has tank-removal invoices, but the related Illinois EPA release file remains open for corrective action.
- The invoices address equipment removal.
- The open incident concerns environmental consequences and remaining program work.
Answer: Describe both facts. Do not advertise completed remediation based only on the removal invoice.
The planned use conflicts with the NFR restriction
An NFR letter relies on commercial use and a groundwater-use restriction. The buyer plans housing and a drinking-water well.
- The proposed uses differ from the assumptions and restrictions in the letter.
- A broker cannot promise that the letter approves the new plan.
Answer: Have the actual letter, controls and proposed use reviewed by environmental and legal professionals.
A buyer is asked to assume the removed-tank file
Registered tanks have been removed, no NFR letter has been issued for the incident and a buyer is asked to sign an Election to Proceed as Owner as routine closing paperwork.
- Illinois EPA describes an election route for a qualifying ownership interest at a removed-tank site.
- The election carries tank-owner responsibilities and liabilities and cannot be withdrawn once filed.
- It does not itself guarantee fund eligibility or reimbursement.
Answer: Obtain legal and environmental advice before making the election; a brokerage checklist is not enough.
Mistakes to avoid
- A known tank matters only if it is leaking. Item 21 asks about tank awareness. Presence and a known release are different facts.
- Every heating-oil tank is exempt. The cited full exclusion is for exclusive consumptive heating use on a farm or residence. Do not extend it automatically to commercial heating tanks.
- A tank in an underground room is necessarily a regulated UST. Apply the rule's location, floor and visibility conditions, as well as the rest of the definition.
- A registered tank is a clean-site certificate. Check the separate release, assessment and corrective-action history.
- Every alarm can wait until a sale closes. Apply the immediate-reporting rule and its actual exceptions. Transaction timing is not an exception.
- The UST Fund pays every buyer's environmental bill. Eligibility, deductible, cost and payment conditions are separate. Buying land, registering a tank or filing an election does not alone establish reimbursement.
- A no answer on the seller report guarantees there is no tank. The report is based on seller knowledge and is not a warranty or a substitute for an appropriate inspection.
Check your understanding
These are original teaching questions, not recalled or predicted PSI questions. Answer first, then explain why the other choices fail.
1. For a covered Illinois home sale, the seller knows a buried tank was used exclusively for residential heating oil. It qualifies for the regulatory exclusion. What is the best item 21 answer?
- Have the buyer answer for the seller
- Yes, with an explanation of the known underground fuel tank
- No, unless a leak has been proved
- No, because only registered tanks count
Show answer and explanation
Answer: B. Yes, with an explanation of the known underground fuel tank
The seller-report question is about actual awareness of underground fuel tanks. The regulatory exclusion and absence of a known leak do not erase the known physical feature. The seller supplies the knowledge-based report.
2. Assume regulated substance and no exclusion. A 1,200-gallon total system has 150 gallons of system volume below ground. What is the relevant result?
- Every system must be completely buried
- The amount of fuel currently stored decides
- 12.5%, so the volume element is met
- 1.25%, so the volume test fails
Show answer and explanation
Answer: C. 12.5%, so the volume element is met
150 divided by 1,200 is 0.125, or 12.5%. The definition counts system volume, including connected underground piping. Meeting that element alone would not override an exclusion or replace the regulated-substance test.
3. Who reports a regulated UST ownership change, and when?
- The subsequent owner, within 30 days after acquisition
- The buyer, at the next five-year inspection
- The listing broker, instead of the new owner
- The seller, only after a future release
Show answer and explanation
Answer: A. The subsequent owner, within 30 days after acquisition
Section 176.440(g) assigns the ownership-change report to each subsequent owner within 30 days after acquisition. It is separate from seller disclosure and new-tank-equipment sale notice.
4. A release-detection device was defective, immediately repaired and additional monitoring did not confirm the initial result. No other evidence exists. Which is correct?
- Every device fault proves a release
- These facts fit the specified exception to that monitoring-results reporting trigger
- All monitoring duties disappear permanently
- Waiting until closing is the relevant exception
Show answer and explanation
Answer: B. These facts fit the specified exception to that monitoring-results reporting trigger
Section 176.300(a)(3)(A) requires the defect, immediate repair/recalibration/replacement and nonconfirmation through additional monitoring. The exception is tied to that trigger; it does not excuse ignoring independent release evidence.
5. Tank-removal invoices are available, but the related Illinois EPA incident remains open. Which statement is supported?
- The whole parcel is clean for every use
- The invoices automatically cancel the incident
- The broker may issue an NFR letter
- Equipment was removed, while corrective action remains a separate open issue
Show answer and explanation
Answer: D. Equipment was removed, while corrective action remains a separate open issue
Removal and corrective-action completion answer different questions. State the documented equipment work and open incident accurately. An invoice is not an agency closure letter or an unrestricted-use warranty.
6. An NFR letter restricts use to commercial activity and prohibits groundwater consumption. A buyer plans homes with drinking-water wells. What is the best response?
- Discard the letter because it mentions contamination
- Assure the buyer that NFR permits every use
- Treat the seller report as an amendment of the NFR letter
- Have the letter, controls and proposed use reviewed by qualified environmental and legal professionals
Show answer and explanation
Answer: D. Have the letter, controls and proposed use reviewed by qualified environmental and legal professionals
The planned uses conflict with the stated restrictions. The letter must be read within its scope and conditions. Neither brokerage assurances nor a seller-report answer changes the environmental controls.
7. Which fact belongs most directly in the Illinois EPA LUST file rather than being established by OSFM registration alone?
- The broker's commission split
- The seller's preferred closing date
- Progress and agency decisions on corrective action for a reported release
- The buyer's mortgage rate
Show answer and explanation
Answer: C. Progress and agency decisions on corrective action for a reported release
Illinois EPA oversees the release incident's remedial activities and reviews plans and reports. OSFM registration answers tank/facility questions; it is not proof of cleanup completion.
8. A buyer is considering an Election to Proceed as Owner for a qualifying removed-tank site with no NFR letter. Which caution is correct?
- It carries owner responsibilities and liabilities and cannot be withdrawn once filed
- It guarantees all cleanup costs will be reimbursed
- It can always be withdrawn immediately after filing
- The election is automatically required in every Illinois home sale
Show answer and explanation
Answer: A. It carries owner responsibilities and liabilities and cannot be withdrawn once filed
Illinois EPA warns of those consequences. The route has qualifying facts and does not itself settle fund eligibility or payment. Obtain appropriate advice before electing; it is not ordinary brokerage form completion.
Common questions
Must an Illinois seller disclose an underground fuel tank if it has never leaked?
For a covered home sale, item 21 asks whether the seller is aware of underground fuel storage tanks. It does not require proof of leakage before a known tank is reported. Explain a yes or not-applicable response as the form directs.
Does an excluded residential heating-oil tank still belong on the seller report?
Yes, when the covered seller knows the underground fuel tank exists. The separate regulatory exclusion does not change that knowledge. It also does not establish whether the soil is contaminated.
What makes a system a regulated UST in Illinois?
Start with regulated substances and the at-least-10% system-volume test, including connected underground piping. Then apply Section 174.100's exclusions. A buried appearance alone is insufficient, and a partial exclusion is not a release from every requirement.
Is the 1,100-gallon exclusion the same as the heating-oil exclusion?
No. The cited 1,100-gallon limit concerns farm or residential motor-fuel storage for noncommercial purposes. The separate exclusion for exclusive farm or residential consumptive heating-oil use has no capacity cap. Commercial heating tanks need their own analysis.
Are septic tanks and basement tanks treated the same way?
Septic tanks are expressly excluded. For a tank in an underground room or vault, apply the specified floor-location and visibility conditions, including visibility from all sides, top and base. Do not classify every basement tank from its address or elevation alone.
What is the Illinois UST ownership-change deadline?
For a regulated UST ownership change, Section 176.440(g) requires the subsequent owner's report within 30 days after acquisition. The electronic filing includes the Authorization to Submit, facility property PIN and ownership evidence. This is not the home seller's precontract disclosure deadline.
Must every suspected release wait for confirmed contamination?
No. Section 176.300 requires immediate IEMA reporting for its specified suspected-release triggers, with stated operating and monitoring exceptions. When a suspected release presents a hazard to life, an immediate 911 call is also required. The rule assigns the regulatory duty to owners or operators; do not delay an emergency response to finish a property transaction.
Does tank registration or removal prove the site is clean?
No. Registration, equipment removal, sampling and release cleanup are distinct records. Review the Illinois EPA incident history and relevant technical and agency documents. A database search also does not replace an appropriately scoped environmental assessment.
What does a No Further Remediation letter mean?
For a LUST incident, it signifies no further corrective action under the applicable program requirements. Read the actual scope, terms, controls and recording requirements. Land-use or groundwater restrictions can remain, and violating the conditions can jeopardize the letter. It is not a warranty covering every condition and future use.
Does an NFR letter for a LUST incident cover every environmental problem on the parcel?
Do not assume so. Identify the program and incident addressed and what was investigated. Other contaminants, areas or later conditions may need separate review. A focused Site Remediation Program letter and a LUST letter also have different program scopes.
What should a buyer ask for when a release is reported?
Obtain the OSFM facility and ownership records, removal and assessment documents, Illinois EPA incident status, reports and correspondence, any NFR letter and its controls, and funding determinations if relevant. Have qualified environmental and legal professionals evaluate the records, planned use and contract risk.
Does buying the property guarantee access to the UST Fund?
No. OSFM eligibility and deductible determinations, approved work, eligible costs and payment conditions matter. Illinois changed parts of the deductible and payment-review rules effective January 1, 2026. Do not use an older general fact sheet to promise a particular deductible or reimbursement.
What is the Election to Proceed as Owner?
Illinois EPA describes an election route for a person with an ownership interest at a qualifying removed-tank site where corrective action has not resulted in an NFR letter. It brings tank-owner responsibilities and liabilities, cannot be withdrawn after filing and does not itself guarantee fund payment. Obtain advice before deciding. If the tanks remain in the ground, the agency describes the ordinary ownership/registration route instead; do not apply the removed-tank election indiscriminately.
Does a seller have to commission tank testing solely to fill out the report?
Section 77/25 does not require a specific investigation or inquiry to complete the disclosure statement. Actual knowledge and existing information still matter. If a seller learns before closing that the delivered report contains an error, inaccuracy or omission, Section 77/30 requires a written supplement. Buyer due diligence is a separate question. The form is not a warranty and its no-investigation rule does not authorize a knowingly false answer.
Can a broker fill in the seller answer or certify cleanup?
The seller supplies the knowledge-based report. The broker should communicate known facts accurately, meet the applicable disclosure duties and obtain the right professional help. A real estate license does not supply environmental sampling, regulated UST contracting or legal authority.
Are these official PSI questions or a readiness score?
No. These eight original questions teach the identified distinctions. They do not reproduce PSI questions or establish that a practice percentage predicts passing. Explain why each answer fits and what changed fact would alter it.
Keep practising
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Put environmental disclosure into practice
Distinguish the property, person and condition covered by each disclosure rule.
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Official sources and scope
Checked October 24, 2026 against the current PSI outline, OSFM adopted rules and Illinois EPA guidance. Relevant first-party indexed Illinois statutory text was read where direct ILGA requests failed. The OSFM index links adopted August 2024 editions; Section 174.100 and Section 176.440 retain May 2023 amendment notes, and Section 176.300 retains its October 2018 note. Those are provision dates, not new October 2026 effective dates. The older buyer fact sheet is used for the election and records discussion, not a current deductible quote. The enacted 2026 funding change takes precedence over an older general summary. The agency funding notice uses July 8, 2010 in one historical description, while the enacted text uses June 8, 2010. This guide avoids teaching a deductible date table or assigning an individual amount; use the enacted provision and agency determination for a live file.
- PSI Illinois booklet, June 24, 2026: Illinois IV.E.4
- 765 ILCS 77/35: seller report, item 21 and form instructions
- 765 ILCS 77/20, /25 and /30: delivery, knowledge and supplements
- OSFM Part 174: Section 174.100 definitions and exclusions
- OSFM Part 176: reporting, assessment and ownership notification
- OSFM current UST rule index and adopted editions
- OSFM UST records, licensed work and funding questions
- Illinois EPA LUST program: incident review and closure
- Illinois EPA: NFR program scope, controls and recording
- Illinois EPA: buyer records and Election to Proceed as Owner
- Public Act 104-291: funding amendments effective January 1, 2026
- Illinois EPA: January 2026 deductible and payment-review changes
- 225 ILCS 454/15-25: seller broker duties to buyer customers
This is exam preparation, not advice for a specific transaction. State law and the applicable facts control. Our editorial and corrections process explains how to report an issue.