The UST inventory log — what the rules actually ask you to keep

Your underground storage tanks sit inside a release-detection system: the rules want proof, on an ongoing basis, that fuel isn't leaving the ground-side of your business unnoticed. For thousands of independent stations, the paper backbone of that proof is the inventory log. Here's what it holds and why.

What goes in the log, per tank

• Daily stick readings — the measured fuel level, converted to gallons with the tank's chart. Georgia's UST guidance is explicit: stick readings every day, for each tank.
• Deliveries — every load, with its date and bill-of-lading gallons.
• Sales — from pump totalizer readings, so the day's movement is measured, not guessed.
• The monthly comparison — book inventory (openings + deliveries − sales) against the physical stick, with the difference written down, not smoothed over.

The monthly standard, in plain numbers

The federal inventory-control method (40 CFR Part 280, Subpart D) reconciles book to physical at least monthly and is built to detect a release of 1% of the month's flow-through plus 130 gallons. Exceed that in two consecutive months and you're in suspected-release territory — investigation and reporting duties attach. That is why the log isn't busywork: it's the record an inspector asks for, and the record that stands between a bad month and a very expensive one.

How long do you keep it?

Georgia's guidance says compliance records — the daily readings, the month-end logs, the monthly reports they feed — are retained for three years. Other states set their own periods; check yours. A shoebox of paper sheets technically qualifies. A book that keeps every day, flags the exceptions, and can show an inspector a clean month-end history is the same records with the work taken out.

What this log is — and is not

Keeping a daily inventory log supports your compliance records. It does not, by itself, make any software a certified release-detection method, and it is not statistical inventory reconciliation (SIR) — SIR is a vendor-run statistical method with its own certification. Many stations use inventory control alongside another approved release-detection method. Know which methods your tanks are on file as using, and keep doing those. The log's job is narrower and more practical: your numbers, every day, in order, with the exceptions visible while they're still cheap to explain.

Official sources: Summarized UST Compliance Inspection Records Guidance (Georgia) — daily stick readings, month-end logs, three-year retention; 40 CFR Part 280, Subpart D — federal release-detection rules including inventory control.

Keep the log in the free book

More guides: Daily tank reconciliation · Fuel variance · Days-to-empty