How to stick an oil tank
Float gauges drift. A wooden stick does not. Sticking the tank takes two minutes and gives you the number your oil company would trust. Here is the procedure for above ground tanks, and further down, for buried tanks read through the fill pipe.
Above ground tanks
- Use a clean, dry wooden stick. A 48″ dowel or yardstick covers any above ground tank. Never use anything that could spark against steel.
- Open an opening on top. The 2″ fill cap unscrews counterclockwise. If the fill is outside and hard to reach, an unused tapping plug on top of the tank works the same way.
- Lower the stick gently to the bottom. Straight down until it touches. Older tanks hold sludge at the bottom; a hard stab stirs it toward your filter.
- Pull it out and read the wet line. Oil leaves a clean dark line. Read the inches from the stick's bottom end.
- Convert with your tank's chart. A 275 vertical at 20″ holds about 120 gallons. Other sizes are on the charts page.
Buried (underground) tanks
No visible tank but an oil-fired burner usually means a buried tank, common at older homes. You read it through the fill pipe, the capped pipe at grade level, often inside a small concrete or cast iron fill box.
- Use a longer stick. The fill pipe adds a riser between grade and the tank top. A 6 to 8 foot wooden stick or a folding rule covers most installations.
- Unscrew the fill cap. If it has not moved in years, penetrating oil and a pipe wrench beat brute force. Do not hammer on it.
- Lower the stick until it rests on the tank bottom. It passes down the riser and into the tank. Keep it vertical.
- Read only the wet line. The dry length above it is riser, not tank. If the wet line reads 30″ on a 48″ diameter underground tank, check the 550 chart or 1000 chart for gallons.
- Recap firmly. Water in the fill box must stay out of the tank.
What a stick reading cannot tell you
- A curved or offset fill pipe can stop the stick before the true bottom. If the stick never reads more than a foot even right after a fill, the geometry is fooling you; ask your oil company to gauge it on the next delivery.
- Tilted tanks read high or low depending on which end the fill sits over. Above ground tanks are even pitched on purpose, about a quarter inch per foot toward the outlet, so the oil and any water walk to the filter. Stick the same opening every time, and note the reading after a known full fill once as your tank's own benchmark.
Common questions
How often should I stick my tank?
Once or twice a month in the heating season, weekly during a cold snap, and before every delivery if you do not have automatic delivery. Logging the dates and readings tells you your burn rate.
Can I use a metal rod or tape measure?
Wood is the standard: it cannot spark, it will not scratch tank coatings, and oil reads clearly on it. A steel tape with a brass plumb works but wipe it fully dry first or the line smears.
My stick will not reach the bottom. What now?
On a buried tank the riser may be longer than your stick, or the fill pipe may bend. Use a longer stick first. If it still will not seat, have the tank gauged at the next delivery rather than guessing.
Is the gauge or the stick right when they disagree?
The stick. Float gauges stick, drift, and read in coarse fractions. See reading an oil tank gauge for what the gauge is still good for.