- Official section
- Illinois IV.E.4: Underground Storage Tanks
- Broker weight
- Part of 25% of the Illinois state portion
- Expected scored items
- The current PSI broker outline assigns 10 of 40 state items to Disclosures
Illinois UST disclosure exam guide
Illinois underground storage tank disclosure
A buried tank creates three separate files. The seller report asks whether a covered seller knows an underground fuel tank exists. OSFM rules ask whether the system is a regulated UST and whether ownership, operation, or release events were reported. Illinois EPA records ask whether a release entered cleanup and reached an NFR Letter. Never collapse those files into one checkbox.
Last updated: August 1, 2026
What does current Illinois authority require?
Short answer: For a covered Illinois home sale, the seller truthfully answers item 21 about actual awareness of underground fuel storage tanks, even if a residential tank is excluded from the regulatory UST definition. A regulated UST generally holds regulated substances with at least 10% of the system volume below ground, subject to exclusions. A new regulated-UST owner reports the ownership change to OSFM within 30 days after acquisition. Evidence of a suspected release triggers immediate reporting under the UST rules, and Illinois EPA oversees a reported leaking-UST cleanup. Registration, tank presence, a release incident, and an NFR Letter each establish different facts.
This guide applies the Illinois Residential Real Property Disclosure Act, 41 Illinois Administrative Code Parts 174 and 176, and Illinois EPA or OSFM guidance through August 1, 2026. It is exam preparation, not environmental assessment, tank-contracting, cleanup, insurance, tax, or legal advice for a particular facility.
Where is this tested on the Illinois outline?
- Topic
- Seller-report tank item
- What to know
- Residential Real Property Disclosure Report, item 21, seller awareness, underground fuel storage tank, property, yes, no, not applicable, explanation, actual knowledge, no special inquiry, material defect, before contract, receipt, and supplement
- Best exam move
- Answer the state home-sale form question before deciding whether the known tank falls inside a regulatory UST program.
- Topic
- Regulatory UST definition
- What to know
- One tank, combination of tanks, connected underground pipe, ancillary equipment, cathodic protection, containment system, regulated substance, accumulation, 10% or more below ground, vault, earthen cover, emergency generator tank, petroleum, hazardous substance, and system volume
- Best exam move
- Test substance, system components, below-ground percentage, and every exclusion instead of relying on the word buried alone.
- Topic
- Common full exclusions
- What to know
- Farm tank, residential tank, 1,100 gallons or less, motor fuel, noncommercial purpose, residential heating oil, farm heating oil, consumptive use, septic tank, regulated pipeline, wastewater treatment tank, surface impoundment, pit, pond, lagoon, stormwater system, wastewater collection, flow-through process tank, emergency spill tank, and liquid trap
- Best exam move
- A tank can be physically below ground yet excluded from the defined UST category.
- Topic
- Location and capacity exclusions
- What to know
- Basement, cellar, mine working, drift, shaft, tunnel, vault, on floor, above floor, visible from all sides, visible top and base, 110 gallons or less, abandoned in place, inert material, hydraulic lift, electrical equipment, operational purpose, and de minimis concentration
- Best exam move
- Visibility and location can make a tank in an underground room different from a tank buried in soil.
- Topic
- Seller-report versus regulatory classification
- What to know
- Known residential heating-oil tank, regulatory exclusion, reportable physical feature, underground fuel, tank presence, no answer, yes answer, explanation, current use, out of service, abandoned, removed, closure document, and actual knowledge
- Best exam move
- Do not use a regulatory exclusion to justify a false no answer about a known underground fuel tank on the seller report.
- Topic
- OSFM registration and files
- What to know
- Office of the State Fire Marshal, Division of Petroleum and Chemical Safety, facility ID, Notification for Underground Storage Tanks, Authorization to Submit, tank record, owner, operator, product, status, installation, registration fee, public UST database, FOIA, contractor, and compliance record
- Best exam move
- Use OSFM records for registration and system status, not as a substitute for Illinois EPA release and cleanup files.
- Topic
- Ownership change
- What to know
- Subsequent owner, acquisition, 30 days, electronic notification, new owner, information change, property identification number, PIN, deed, property-tax record, contract, lease, proof of legal ownership, facility-specific filing, and owner contact
- Best exam move
- Start the regulatory clock at acquisition and assign the notification to the new regulated-UST owner.
- Topic
- Seller of a tank versus seller of real property
- What to know
- New tank, recertified tank, seller of equipment, purchaser of tank, owner's notification obligations, electronic form, real-property transfer, home seller, tank manufacturer, supplier, and Section 176.440(h)
- Best exam move
- The rule about selling a new or recertified tank concerns tank equipment, not a universal form for every sale of land containing an old tank.
- Topic
- Suspected release
- What to know
- Immediate report, IEMA-OHS, owner, operator, released regulated substance, free product, vapor, soil, basement, sewer, utility line, surface water, unusual operating condition, erratic dispenser, sudden product loss, unexplained water, interstitial space, defective component, repair, and investigation
- Best exam move
- Recognize evidence that activates release reporting rather than waiting for a completed real estate transaction.
- Topic
- Site assessment and removal
- What to know
- Owner or operator, site assessment, contamination, sample, tank removal, OSFM Site Assessment Report, backfill, groundwater, stored substance, release identification, licensed contractor, removal permit, closure, abandonment in place, and technical report
- Best exam move
- A broker can request existing records but should not select samples, declare soil clean, or direct regulated tank work.
- Topic
- Leaking UST program
- What to know
- Illinois EPA, LUST incident, reported release, corrective action, remediation objective, technical plan, budget, soil, groundwater, vapor, fire, explosion, drinking water, public database, incident number, project manager, correspondence, and cleanup status
- Best exam move
- Once a release is reported, follow the incident through Illinois EPA records instead of stopping at the OSFM registration entry.
- Topic
- No Further Remediation Letter
- What to know
- NFR Letter, program requirements, remediation objectives, no further corrective action, incident-specific, institutional control, engineered barrier, land-use assumption, recorded document, terms, conditions, property owner summary, legal description, parcel index number, and current status
- Best exam move
- Read the actual letter and its controls; do not translate NFR into a guarantee that the entire property is contamination-free.
- Topic
- Buyer due diligence
- What to know
- OSFM registration, tank removal, fund eligibility, deductible, Illinois EPA database, cleanup report, FOIA, correspondence, NFR Letter, environmental site assessment, Phase I, Phase II, environmental professional, attorney, lender, insurer, contract contingency, access, and allocation
- Best exam move
- A yes answer is the beginning of fact gathering, not a professional conclusion or automatic contract outcome.
- Topic
- Election to Proceed as Owner
- What to know
- Removed registered tank, unresolved corrective action, buyer, ownership interest, election form, Illinois EPA, Title XVI, tank owner, responsibilities, liabilities, UST Fund, OSFM eligibility, cannot withdraw, private attorney, and prepurchase decision
- Best exam move
- Treat the election as a consequential legal and environmental decision, not routine brokerage paperwork.
- Topic
- Broker boundaries and disclosure
- What to know
- Known tank, known release, actual knowledge, latent material adverse physical fact, customer, timely disclosure, seller report, false answer, environmental professional, licensed UST contractor, attorney, OSFM, Illinois EPA, delivery proof, document log, and no safety guarantee
- Best exam move
- Communicate the known facts and route the file while qualified people classify, test, remove, remediate, insure, and interpret legal consequences.
The TANKS file
- Tell what is known. Get the covered seller's actual-knowledge answer about underground fuel tanks into the Illinois report before contract signing.
- Analyze regulation separately. Apply the 10% definition, regulated-substance element, and every full or partial exclusion.
- Notify on ownership change. A new owner of a regulated UST files the OSFM information within 30 days after acquisition.
- Keep release records distinct. Report suspected releases as required and follow the Illinois EPA LUST incident through corrective action.
- Study the closure evidence. Compare removal records, site assessments, agency correspondence, and any NFR Letter rather than trusting a label.
- Stay within brokerage scope. Disclose known facts, document delivery, and refer classification, testing, contracting, cleanup, liability, and coverage.
- Record or event
- Seller report item 21
- What it proves
- Seller's actual awareness of underground fuel tank
- What it does not prove
- Regulatory status or soil condition
- Record or event
- UST definition analysis
- What it proves
- Whether system fits regulated category
- What it does not prove
- Whether a release occurred
- Record or event
- OSFM registration
- What it proves
- Facility, tank, owner, product, and status information
- What it does not prove
- Cleanup completion
- Record or event
- New-owner notification
- What it proves
- Ownership change reported within regulatory process
- What it does not prove
- Seller disclosure was timely
- Record or event
- Suspected-release report
- What it proves
- Specified evidence was reported
- What it does not prove
- Final extent or cost of contamination
- Record or event
- Site assessment
- What it proves
- Sampling during defined tank work
- What it does not prove
- Universal condition of all property
- Record or event
- Illinois EPA LUST file
- What it proves
- Reported-release corrective-action history
- What it does not prove
- Every environmental condition on parcel
- Record or event
- NFR Letter
- What it proves
- No further corrective action for identified incident under its terms
- What it does not prove
- Unqualified clean-site warranty
- Record or event
- Environmental professional report
- What it proves
- Opinion within stated scope and date
- What it does not prove
- Permanent guarantee after conditions change
Which Illinois distinctions matter most?
- Terms
- Underground fuel tank vs. regulated UST
- Difference
- The seller report asks about a known underground fuel storage tank. Regulatory UST status depends on substance, below-ground volume, capacity, use, location, and listed exclusions.
- Question cue
- Physical disclosure term versus program definition.
- Terms
- Tank presence vs. release
- Difference
- A tank can exist without a known leak. A release is a spilling, leaking, escaping, or similar movement from the UST into groundwater, surface water, or subsurface soil.
- Question cue
- Equipment exists versus product entered environment.
- Terms
- Registration record vs. cleanup record
- Difference
- OSFM registration identifies facility, owner, tanks, product, and status. Illinois EPA LUST records track reported release investigation and corrective action.
- Question cue
- Tank system file versus contamination incident file.
- Terms
- Out of service vs. removed
- Difference
- An out-of-service tank remains in place under a regulated status. Removal physically takes the system out under closure procedures and includes a site-assessment process.
- Question cue
- Inactive equipment versus physical closure work.
- Terms
- Removed tank vs. remediated release
- Difference
- Removing a tank ends its physical presence but does not automatically complete corrective action for contamination already released.
- Question cue
- Remove source versus address environmental impact.
- Terms
- NFR Letter vs. clean-property warranty
- Difference
- An NFR Letter resolves further corrective action for the identified incident under the relevant program and its terms. It does not promise that no other environmental condition exists.
- Question cue
- Program closure document versus universal guarantee.
- Terms
- Seller disclosure vs. buyer due diligence
- Difference
- The seller reports actual awareness on the applicable form. The buyer may investigate registration, releases, cleanup, engineering, cost, coverage, and contract risk through qualified people.
- Question cue
- Owner knowledge statement versus independent inquiry.
- Terms
- Actual knowledge vs. special investigation
- Difference
- The Illinois seller report does not require a special investigation solely to complete the form. Existing tank records, observations, prior work, or agency correspondence can still establish actual knowledge.
- Question cue
- No new search duty does not erase known information.
- Terms
- New-owner notice vs. seller disclosure
- Difference
- The covered residential seller's report arrives before the sales contract. A new regulated-UST owner reports the ownership change to OSFM within 30 days after acquisition.
- Question cue
- Precontract buyer information versus post-acquisition agency notification.
- Terms
- Tank-equipment sale notice vs. land sale
- Difference
- Section 176.440(h) addresses a person selling a new or recertified tank for use as a UST. It is not the seller-report rule for land with an existing tank.
- Question cue
- Purchase of tank equipment versus transfer of real property.
- Terms
- Broker observation vs. environmental conclusion
- Difference
- A broker may observe fill pipes or possess an agency record. Determining whether a regulated UST exists, a release occurred, cleanup is sufficient, or liability transfers requires the relevant regulator or professional.
- Question cue
- Report fact versus certify status.
- Terms
- Residential heating-oil exclusion vs. no disclosure
- Difference
- A qualifying residential heating-oil tank can be excluded from the UST definition while remaining a known underground fuel storage tank that belongs on the applicable seller report.
- Question cue
- Regulatory classification does not rewrite seller knowledge.
How does the Illinois rule apply?
A known home heating-oil tank
Scenario: A seller knows a buried tank supplied heating oil to a single-family home. The tank is excluded from the regulated UST definition, so the seller marks no on item 21.
- The regulatory exclusion and seller-report question serve different purposes.
- Item 21 asks whether the seller is aware of an underground fuel storage tank, which the seller is.
Answer: Correct the report and explain the known tank. Then obtain qualified advice about its status, condition, removal, and any release.
A buyer sees an active registration
Scenario: The OSFM database lists two registered gasoline tanks at a service-station property. The buyer concludes there cannot be contamination because the tanks are registered.
- Registration addresses tank and facility administration.
- The buyer must separately review suspected-release, LUST, site-assessment, and corrective-action records.
Answer: Do not treat registration as environmental clearance; investigate the separate Illinois EPA and technical files.
The property sells and the regulated tanks remain
Scenario: A buyer acquires a commercial parcel with registered USTs on June 1 and plans to update OSFM records at year end.
- Change of ownership is a reportable information change.
- The subsequent owner has 30 days after acquisition to complete the required electronic notification and ownership evidence.
Answer: File the new-owner notification within 30 days rather than waiting until year end.
The tanks are removed, but cleanup remains open
Scenario: A seller provides tank-removal invoices. Illinois EPA records show the related release incident is still under corrective action.
- Removal establishes that the equipment was taken out under a process.
- The open LUST file shows the environmental incident has not yet reached program closure.
Answer: Describe both facts accurately. Do not advertise the site as remediated merely because the tanks are gone.
An NFR Letter contains a land-use control
Scenario: A seller says an NFR Letter proves the parcel is clean for any future use, but the letter relies on a commercial land-use assumption and an institutional control.
- An NFR Letter must be read with its incident, objectives, terms, and controls.
- A planned residential use may not match the basis on which no further action was determined.
Answer: Refer the letter and planned use to environmental and legal professionals instead of making a clean-for-any-use claim.
A broker smells fuel vapor
Scenario: During a showing, the broker notices strong petroleum-like vapor in the basement of a property with a known UST facility next door.
- Vapors in a basement can be evidence relevant to suspected-release rules and an immediate safety response.
- The broker should not test the air personally or promise the source is the neighboring tank.
Answer: Stop treating the matter as ordinary marketing, document the observation, alert the proper parties, and use emergency, regulatory, and environmental professionals as the circumstances require.
Where do candidates misread the Illinois rule?
- Trap
- Every underground tank is a regulated UST.
- Correction
- The 10% definition includes numerous use, capacity, substance, and location exclusions.
- Trap
- A regulatory exclusion means the tank may be omitted from the seller report.
- Correction
- The seller report separately asks about known underground fuel storage tanks.
- Trap
- A septic tank is a petroleum UST.
- Correction
- Septic tanks are expressly outside the regulatory UST definition.
- Trap
- Any tank in a basement is underground.
- Correction
- A tank on the floor of an underground area that is visible from all sides, top, and base is excluded from the UST definition.
- Trap
- Registration proves no leak occurred.
- Correction
- Registration and release or cleanup history are different records.
- Trap
- Tank removal automatically closes a release incident.
- Correction
- Source removal and environmental corrective action must be evaluated separately.
- Trap
- An NFR Letter guarantees the entire parcel is clean forever.
- Correction
- It addresses a specific incident and program under stated terms, objectives, assumptions, and controls.
- Trap
- The seller files the new-owner notification before closing for the buyer.
- Correction
- The subsequent regulated-UST owner reports within 30 days after acquisition using its own required information.
- Trap
- Section 176.440(h) creates a property-sale disclosure form.
- Correction
- That subsection concerns a person selling a new or recertified tank as equipment.
- Trap
- A broker may wait for a completed lab report before responding to obvious suspected-release evidence.
- Correction
- Regulated owners or operators have immediate reporting duties in listed circumstances, and safety concerns should be escalated promptly.
- Trap
- A buyer should file an Election to Proceed as Owner as routine paperwork.
- Correction
- The election carries owner responsibilities and liabilities and cannot be withdrawn after filing.
- Trap
- No special seller investigation means existing agency letters may be ignored.
- Correction
- The seller answers from actual knowledge, which can include records already received.
- Trap
- The broker can certify tank closure or soil quality.
- Correction
- The broker transmits facts and records while licensed contractors, regulators, environmental professionals, and attorneys address conclusions.
Can you apply the rule to a fresh scenario?
These questions are original study items aligned to the published outline. They are not copied, recalled, or predicted PSI questions.
1. A covered Illinois home seller knows a buried residential heating-oil tank exists. The tank is excluded from the regulated UST definition. How should item 21 be answered?
- No, because every regulatory exclusion erases the physical tank
- Yes, with the required explanation of the known underground fuel tank
- Leave the entire report unsigned
- Ask the broker to answer from the broker's knowledge
Show answer and explanation
Answer: B
The residential report's actual-knowledge question is separate from regulatory UST classification.
2. What below-ground threshold is part of the Illinois regulatory UST definition?
- At least 1% of tank shell only
- At least 10% of system volume, including connected underground piping
- Exactly 50% of product volume
- Any tank located anywhere in a basement
Show answer and explanation
Answer: B
The definition uses 10% or more beneath the surface and counts the volume of connected underground piping.
3. A buyer acquires a regulated UST facility. When must the ownership change be reported to OSFM?
- Within 30 days after acquisition
- Within five years
- Only when a leak occurs
- At the next property tax reassessment
Show answer and explanation
Answer: A
Section 176.440 treats ownership change as an information change and gives the subsequent owner 30 days after acquisition.
4. Which document most directly shows that Illinois EPA requires no further corrective action for a specified LUST incident under the letter's terms?
- An OSFM registration listing
- A seller's marketing flyer
- A No Further Remediation Letter
- A tank manufacturer's invoice
Show answer and explanation
Answer: C
The Illinois EPA NFR Letter is the program closure document, though its scope and controls must be read carefully.
5. Which statement about a removed tank is correct?
- Removal always proves no release ever occurred
- Removal automatically cancels every Illinois EPA incident
- Removal addresses the equipment, while contamination and corrective action require separate evidence
- Removal can be performed by the listing broker
Show answer and explanation
Answer: C
Physical tank closure and environmental cleanup are separate parts of the file.
How should you review this Illinois topic?
- Session
- 1. Split disclosure and regulation
- Focus
- Seller-report item 21, actual knowledge, underground fuel tank, regulated UST definition, 10% threshold, substance, use, capacity, and exclusions
- Proof you are ready
- Classify 25 tanks as reportable seller knowledge, regulated UST, both, neither, or needing more facts.
- Session
- 2. Map the OSFM file
- Focus
- Facility, tank, registration, owner, operator, product, status, new-owner notice, 30 days, PIN, deed, notification, contractor, and removal
- Proof you are ready
- Build the OSFM record sequence for 10 ownership and closure scenarios.
- Session
- 3. Map the release file
- Focus
- Suspected release, immediate report, IEMA-OHS, site assessment, Illinois EPA, LUST incident, corrective action, remediation objective, and NFR Letter
- Proof you are ready
- Put 20 release and cleanup events into the correct agency and chronological order.
- Session
- 4. Separate evidence
- Focus
- Tank presence, registration, out-of-service status, removal, release report, site assessment, corrective action, institutional control, and NFR Letter
- Proof you are ready
- For each record, state exactly what it proves and what it cannot prove.
- Session
- 5. Assign professional roles
- Focus
- Seller, buyer, broker, sponsoring broker, OSFM, Illinois EPA, UST contractor, environmental professional, attorney, lender, and insurer
- Proof you are ready
- Assign every disclosure, notification, test, removal, cleanup, and legal decision to the right person.
- Session
- 6. Apply TANKS
- Focus
- Tell, analyze, notify, keep release records, study closure, and stay in scope
- Proof you are ready
- Score at least 90% on a fresh UST set and defend each answer without using registration as a clean-site shortcut.
Do not count recognition as mastery. Close the notes and explain the rule, apply it to a new fact pattern, and identify why each distractor fails.
Practice the Illinois rule in context
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Questions students ask about Illinois Underground Storage Tank Disclosure
Must an Illinois home seller disclose an underground fuel tank?
For a covered sale, item 21 of the Illinois Residential Real Property Disclosure Report asks whether the seller is aware of underground fuel storage tanks on the property. The seller answers from actual knowledge and explains a yes or not-applicable response as the form directs.
What is a regulated underground storage tank in Illinois?
Illinois rules generally define a UST system as one or more tanks and connected components used to hold regulated substances when at least 10% of the system volume, including underground connected piping, lies beneath the ground surface. The definition then lists exclusions, so an underground tank and a regulated UST are not always identical.
Is a buried residential heating-oil tank a regulated UST?
A heating-oil tank of any capacity used exclusively for consumptive heating on a farm or residence is excluded from the OSFM UST definition. That regulatory exclusion does not erase a covered home seller's separate duty to answer truthfully about a known underground fuel storage tank on the Illinois seller report.
Is a septic tank an underground storage tank under the Illinois UST rules?
No. A septic tank is listed outside the regulatory UST definition. It is still a physical property feature with its own inspection, disclosure, and system questions, but it should not be mislabeled as a regulated petroleum UST.
What must a new Illinois UST owner report?
For a regulated UST, a change in ownership is a reportable information change. The subsequent owner submits the electronic OSFM notification, authorization, property PIN, and proof of legal ownership within 30 days after acquisition.
What happens if a regulated UST may be leaking?
Illinois rules require owners or operators to report suspected releases immediately to the Illinois Emergency Management Agency and Office of Homeland Security when specified evidence or unusual operating conditions arise, subject to stated exceptions. The Illinois EPA then oversees corrective action after a release is reported.
Does UST registration prove that a property is uncontaminated?
No. Registration identifies the regulated facility and tank status. Release reporting, site assessment, corrective action, and a No Further Remediation Letter answer different questions. A buyer should not treat one registry entry as a clean-site guarantee.
What is an Illinois EPA No Further Remediation Letter?
For a leaking UST incident, the Illinois EPA issues an NFR Letter after the site satisfies the applicable program requirements and remediation objectives. It signifies that no further corrective action is required for that incident under the relevant program, subject to the letter's terms and any controls. It is not a universal statement that no environmental issue can exist anywhere on the property.
What should a buyer review before purchasing property with a UST release?
Illinois EPA advises checking OSFM registration and removal information, Illinois EPA cleanup status, reports, correspondence, fund eligibility questions, and available files. A buyer considering an Election to Proceed as Owner should obtain legal and environmental advice because that election carries owner responsibilities and cannot be withdrawn once filed.
Are these official PSI Illinois broker exam questions?
No. They are original questions aligned to the Illinois broker outline effective June 24, 2026. Illinois statutes, administrative rules, and agency guidance were reviewed through August 1, 2026.
Primary sources
- PSI Illinois Candidate Information Booklet dated June 24, 2026
- 765 ILCS 77, Illinois Residential Real Property Disclosure Act
- 765 ILCS 77/35, current seller report and underground-fuel-tank item
- 41 Illinois Administrative Code 174.100, current UST definitions and exclusions
- 41 Illinois Administrative Code 176.440, UST registration and ownership-change notice
- 41 Illinois Administrative Code Part 176, release reporting and site assessment
- Illinois OSFM UST owner, registration, change, and site-assessment guidance
- Illinois OSFM current UST applications and forms
- Illinois EPA Leaking Underground Storage Tank Program
- Illinois EPA guidance for buyers of property with a reported UST release
- Illinois EPA No Further Remediation Letter guidance
- 225 ILCS 454/15-25, Illinois licensee duties to customers
The current official outline controls the tested scope. Statutes, regulations, and official agency materials control when a general study rule and a jurisdiction-specific rule differ.
Editorial status
Checked against primary sources
The Pass Illinois editorial team last checked this guide on August 1, 2026. Every practice question is an original study item, and the source links above let you verify the rules that support the lesson.