Work out submersible pump selection instantly with clear inputs, formula shown and shareable results.
A submersible pump must lift water from the pumping level, not the static level, so drawdown at design flow is added first. On top of that come the rise to the storage tank, the tank pressure converted at 2.31 feet per psi, and a friction allowance. Each stage of a typical four-inch submersible develops roughly 25 feet of head.
Total dynamic head
TDH = static level + drawdown + surface rise + psi x 2.307 + friction
Stage count
Stages = TDH / head per stage (about 25 ft for a 4 in submersible)
TDH = static level + drawdown + surface rise + psi x 2.307 + friction. A submersible pump must lift water from the pumping level, not the static level, so drawdown at design flow is added first.
In a low-yielding well drawdown can exceed the static depth, doubling the head. Sizing on static level alone leaves the pump unable to deliver its rated flow.
This calculator takes 4 inputs: Static water level below grade, Drawdown at design flow, Rise from wellhead to tank, Pressure required at tank. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.