Fill time · 100 gal
How long to fill a 100 gallon tank
At a typical 8 GPM garden-hose flow: 12 min. Full table below; exact math is volume ÷ flow.
—
| Flow rate | Time | Minutes |
|---|---|---|
| 2 GPM | 50 min | 50.0 min |
| 5 GPM | 20 min | 20.0 min |
| 8 GPM | 12 min | 12.5 min |
| 10 GPM | 10 min | 10.0 min |
| 15 GPM | 7 min | 6.7 min |
| 20 GPM | 5 min | 5.0 min |
| 30 GPM | 3 min | 3.3 min |
| 50 GPM | 2 min | 2.0 min |
Flow-rate reality check: hose bib with good pressure 6–10 GPM; 1/2 HP transfer pump 20–40 GPM; gravity from an IBC barely 5 GPM through a garden fitting. Time a 5-gallon bucket and divide — it beats every nameplate rating. For the volume side, the tank charts give exact gallons at any depth.
FAQ
How long does it take to fill a 100 gallon tank with a garden hose?
A typical hose delivers 6–10 GPM — call it 17 min to 10 min for 100 gallons. Bucket-test your actual flow: a 5-gallon bucket filling in 30 seconds is 10 GPM.
How long with a transfer pump?
At a common 30 GPM transfer rate, about 3 min. At 50 GPM, 2 min.
Does draining take the same time?
Only if the flow is constant. Gravity drains slow as the head drops, so treat these times as a lower bound for draining.