1500 Gallon Underground Oil Tank dimensions

Nominal rating versus real geometry

A tank's name is a trade label. Its geometry is a measurement. On a underground fuel-oil tank these two numbers are related but not equal, and knowing which one you are quoting matters whenever the figure ends up on an invoice, a permit or a purchase order.

Rated 1,500 gal. Computed from the dimensions in the table above: 1,504.0 gal. The label and the geometry agree to within half a percent here, which usually means the published dimensions were themselves derived from the rating rather than measured independently.

Densities are the reference values tabulated on our methodology page, near 60–70 °F. Real fluids vary with temperature, grade and composition — a 10 °F swing moves a hydrocarbon density by roughly 0.4 %. Add the empty vessel weight to get a gross figure.

Siting, backfill and access

Excavation, bedding and backfill matter more than the tank for a buried vessel. The hole has to be big enough for the specified bedding all round, the backfill has to be the material the tank's listing calls for, and the tank has to be held down against flotation — an empty buried tank in a high water table will lift, and a lifted tank breaks its piping.

Plan the gauging access before the tank goes in the ground. You need a riser you can reach with a stick, a known distance from grade to tank bottom, and a fill point a delivery truck can actually reach. Under 40 CFR § 280.43(a) the gauging equipment has to resolve the full tank height to the nearest eighth of an inch, and that is much easier to arrange at installation than to retrofit.

Record the as-built: tank dimensions, orientation, any deliberate slope, the riser height, and the depth to the tank bottom. Every future reconciliation depends on those four numbers, and they are unrecoverable once the hole is closed.

The standards behind this tank

Buried fuel tanks sit inside a federal regulatory programme, 40 CFR Part 280, and a chart like this one is part of how compliance is demonstrated. Under § 280.43(a), inventory control must be capable of detecting a release of 1.0 % of flow-through plus 130 gallons in a month, and the gauging equipment must read the full height of the tank to the nearest one-eighth of an inch. That is the specification your stick and your chart together have to meet.

Manual tank gauging is allowed as the sole release-detection method only for tanks of 550 gallons or less nominal capacity, and for some 551–1,000 gallon tanks that meet the diameter criteria in § 280.43(b). Larger tanks need it in combination with, or replaced by, another method. State programmes approved under 40 CFR Part 281 are often stricter than the federal floor.

Construction is to UL 58 for steel USTs (or UL 1746 for jacketed steel), and installation to NFPA 31 where the tank feeds oil-burning equipment. For a capacity table you can defend, calibrate under ISO 7507 rather than computing from nominal dimensions.

For depth-by-depth volumes on this tank, use the inch-by-inch chart; for a different set of dimensions, the dip chart generator will build one.

Sources and standards

The geometry on this page is computed, not copied. These are the documents that define the units it is expressed in and the codes that govern a underground fuel-oil tank in service.

1. 40 CFR § 280.43 — Methods of release detection for tanksU.S. Environmental Protection Agency, via the electronic Code of Federal Regulationshttps://www.ecfr.gov/current/title-40/chapter-I/subchapter-I/part-280/subpart-D/section-280.43The federal rule that makes tank charts a compliance instrument rather than a convenience. Inventory control must detect a release of 1.0 % of flow-through plus 130 gallons per month; gauging equipment must read the full tank height to the nearest one-eighth of an inch; manual tank gauging is allowed as the sole release-detection method only for tanks of 550 gallons or less (and some 551–1,000 gallon tanks meeting the diameter criteria).
2. 40 CFR Part 280 — Technical Standards and Corrective Action Requirements for Owners and Operators of Underground Storage TanksU.S. Environmental Protection Agency, via the electronic Code of Federal Regulationshttps://www.ecfr.gov/current/title-40/chapter-I/subchapter-I/part-280The whole federal UST programme: design and construction standards (§ 280.20), release detection (Subpart D), operator training and closure. State programmes approved under Part 281 may be stricter.
3. UL 80 — Standard for Steel Tanks for Oil-Burner Fuel and Other Combustible Liquids; UL 58 — Steel Underground Tanks for Flammable and Combustible LiquidsUL Standards & EngagementPaid standard — cited by designation; obtain from the publisher.The construction standards behind the familiar 275 and 330 gallon aboveground heating-oil tanks (UL 80) and steel USTs (UL 58). They govern steel gauge, seams, fittings and leak testing — not gauge-chart accuracy, which is why a listed tank still needs its own capacity table for anything measured.
4. NFPA 31 — Standard for the Installation of Oil-Burning EquipmentNational Fire Protection AssociationPaid standard — cited by designation; obtain from the publisher.Governs how fuel-oil supply tanks are installed, vented, filled and located, including tank-to-appliance clearances and fill and vent piping. Adopted, often with amendments, by most US states.
5. Handbook 44, Appendix C — General Tables of Units of MeasurementNational Institute of Standards and Technology, U.S. Department of Commercehttps://www.nist.gov/document/2026-nist-handbook-44-appendix-cThe legal-metrology reference for U.S. customary units. Fixes the U.S. liquid gallon at exactly 231 cubic inches and tabulates the full liquid-volume chain (minim → fluid dram → fluid ounce → gill → pint → quart → gallon).
6. ISO 7507-1 — Petroleum and liquid petroleum products: Calibration of vertical cylindrical tanks, Part 1: Manual strapping methodInternational Organization for StandardizationPaid standard — cited by designation; obtain from the publisher.Defines how a tank's capacity table (its “strapping table”) is produced from physical measurement, including corrections for plate thickness, shell expansion and tank tilt. It is the reason a real tank's chart rarely matches naive geometry to the last gallon.
7. Methodology — the partial-fill formulas and liquid densities used on this sitetankvolumecalc.comhttps://tankvolumecalc.com/methodology/Every chart value here comes from a closed-form partial-fill formula, not interpolation: circular segments for cylinders, a piecewise obround model for 275/330 heating-oil tanks, and scaled spherical caps for dished heads. Densities and their bases are tabulated there.

Every linked source above was retrieved and checked on 2026-09-02. Factors quoted as exact are exact by definition in the cited document, not rounded by us.