UST inventory reconciliation worksheet
The monthly arithmetic behind federal underground-storage-tank release detection: daily inventory reconciliation against the 1 % + 130 gallon standard, the four-week manual tank gauging test, and the SPCC capacity check — with stick readings turned into gallons for your tank, and a page you can print for the record.
An arithmetic aid, not a compliance determination. Your state UST program may set stricter rules and its own forms; use theirs where they exist. Home heating-oil tanks are outside the federal UST rule.
1 · Daily inventory, monthly reconciliation — 40 CFR 280.43(a)
Each operating day: the opening stick, deliveries (from the receipts), metered sales or withdrawals, and the closing stick, all to the nearest ⅛ inch. Book inventory is opening + deliveries − sales; the difference between the closing stick and the book is the day's over (+) or short (−). Water in the tank bottom is subtracted from both readings. The first four rows are an example — replace them.
| Date | Opening | Delivered | Sold | Closing | Water (in) | Book gal | Over/short | Cumulative |
|---|
2 · Manual tank gauging — 40 CFR 280.43(b)
Once a week, with nothing added or removed for the whole test period: take two consecutive stick readings at the start and two at the end. The averages are compared, and each weekly change and the four-week average are checked against the table in the rule.
| Test | Start reading 1 | Start reading 2 | End reading 1 | End reading 2 | Change |
|---|
3 · SPCC capacity check — 40 CFR 112.1(d)(2)
List the capacity of every aboveground oil container at the facility in gallons, separated by commas. Containers under 55 gallons are not counted.
FAQ
TVC-119/FAQWhat is the inventory control variance for an underground storage tank?
Under 40 CFR 280.43(a), monthly inventory control must be able to detect a release of 1.0 percent of the month's flow-through plus 130 gallons. If the month's cumulative over-or-short is larger than that, the reconciliation has failed and a release is suspected.
Is inventory control enough on its own?
No. Under 40 CFR 280.41, inventory control counts only alongside periodic tank tightness testing, and only for tanks installed on or before April 11, 2016, until ten years after installation. Tanks installed after that date need monthly monitoring under 280.43(g). Your state program may be stricter.
Which tanks can use manual tank gauging alone?
Tanks of 550 gallons or less, and 551–1,000 gallon tanks that are 48 or 64 inches in diameter, using the test times and limits in the 280.43(b) table. Larger tanks up to 2,000 gallons may use it only in place of inventory control, alongside tightness testing.
Does this apply to my home heating oil tank?
Not under the federal rule. 40 CFR 280.12 excludes tanks storing heating oil used on the premises, and farm or residential tanks of 1,100 gallons or less holding motor fuel for non-commercial use. Some states regulate them anyway — check with your state UST program.
When does the SPCC rule apply?
40 CFR 112.1 exempts facilities whose aggregate aboveground oil storage capacity is 1,320 US gallons or less — counting only containers of 55 gallons or more — and whose completely buried capacity outside part 280 is 42,000 gallons or less. Above either figure, the plan requirement applies if the facility could reasonably be expected to discharge oil to navigable waters or shorelines.
Sources and standards
- 40 CFR 280.43 — Methods of release detection for tanksU.S. EPA, via the electronic Code of Federal Regulationshttps://www.ecfr.gov/current/title-40/chapter-I/subchapter-I/part-280/subpart-D/section-280.43(a) inventory control: 1.0 % of flow-through plus 130 gallons; (b) manual tank gauging table.
- 40 CFR 280.41 — Requirements for petroleum UST systemsU.S. EPA, via the electronic Code of Federal Regulationshttps://www.ecfr.gov/current/title-40/chapter-I/subchapter-I/part-280/subpart-D/section-280.41When inventory control and manual tank gauging may be used.
- 40 CFR 280.12 — Definitions (UST exclusions)U.S. EPA, via the electronic Code of Federal Regulationshttps://www.ecfr.gov/current/title-40/chapter-I/subchapter-I/part-280/subpart-A/section-280.12
- 40 CFR 112.1 — General applicability (SPCC)U.S. EPA, via the electronic Code of Federal Regulationshttps://www.ecfr.gov/current/title-40/chapter-I/subchapter-D/part-112/subpart-A/section-112.1(d)(2): 42,000 gal completely buried; 1,320 gal aboveground, counting containers of 55 gal or more.
- Doing Inventory Control Right: For Underground Storage TanksU.S. Environmental Protection Agency, Office of Underground Storage Tankshttps://www.epa.gov/ust/doing-inventory-control-right-underground-storage-tanks
- Manual Tank Gauging for Small Underground Storage TanksU.S. Environmental Protection Agency, Office of Underground Storage Tankshttps://www.epa.gov/ust/manual-tank-gauging-small-underground-storage-tanks
Every linked source above was retrieved and checked on 2026-11-01.