Almost every deal that falls apart in due diligence on a gas station falls apart because of an underground storage tank problem nobody saw coming. Sometimes it's a six-figure remediation. Sometimes it's “just” an open state notice of violation that nobody disclosed. Either way, you find out two weeks before close and the deal collapses.
Here's the document list to put in front of every seller before you write a serious LOI. If they can produce all ten quickly, you're probably looking at a clean station. If they hesitate on any of them, dig.
1. Tank tightness / integrity test (last 2 years)
Annual or biennial depending on state. Should show pass on every tank and every line. Failures or retests are not automatically dealbreakers, but you want the corrective-action paperwork.
2. UST registration certificate
Issued by the state environmental agency. Lists tank capacity, construction (steel vs fiberglass), installation date, contents. Should match what's actually in the ground. Mismatches are surprisingly common after decades of changes.
3. State UST compliance inspection report (last 2 years)
The state walks the property and writes you up on whatever they find. You want a notice of compliance, not a notice of violation, and certainly not an open consent order. If there's an NOV, ask for the closure letter that proves it's resolved.
4. Cathodic protection test (annual, for steel tanks/lines)
Steel UST systems are required to have cathodic protection (sacrificial anodes or impressed current) and an annual test showing it's working. Missing tests don't mean the protection is broken — but it's a flag for a sloppy operator.
5. Stage I / Stage II vapor recovery test
Required in most metro areas (anywhere with an EPA ozone non-attainment designation, plus most of California). Tests run annually or biennially. A failed test means downtime to fix dispenser hardware.
6. Spill bucket and overfill prevention test
Required at every fill port. Tests run annually. Cracked spill buckets are a frequent NOV trigger and a hint that the previous operator wasn't inspecting their own equipment.
7. Line leak detector functionality test
Mechanical or electronic. Tested annually. Failures here are serious because a line leak is the most expensive remediation scenario.
8. Inventory reconciliation (SIR) reports
If the seller uses statistical inventory reconciliation as their release-detection method (instead of automatic tank gauging), you want twelve months of monthly SIR reports showing pass status. A single “inconclusive” month is a question to ask. Multiple is a real concern.
9. Phase I Environmental Site Assessment
A Phase I is a desktop + walk-through review by a consultant looking at chain of title, historical aerial photos, regulatory databases, and visible site conditions. It identifies “recognized environmental conditions” — RECs — that warrant further investigation. Most lenders require one before funding. If the seller hasn't had one done in the last 12 months, you'll be paying for a fresh one anyway. Ask if they have an older report you can review while you wait.
10. Insurance policy + claims history
Commercial general liability + pollution liability + employment practices. Five-year claims history (a “loss-run” from the carrier). The claims history tells you what actually happens at this station — not what the seller says happens.
If something's missing
A missing document isn't automatically a dealbreaker. It's a question. Ask the seller why, get the answer in writing, and adjust your offer (and your contingency package) accordingly. The deals we've seen close cleanly are the ones where the seller hands over all ten documents the day after the NDA gets signed. The deals that blow up are the ones where document-by-document foot-dragging eats six weeks before someone admits the Phase II ESA was never done.