Home Jet Pump or Submersible? How to Choose for a Shallow Well
Short answer: Choose on the pumping water level, not the well depth. A jet pump lifts water by suction, and suction is limited by atmospheric pressure to roughly 7.5–8 m (25 ft) of lift in practice. If the water level stays above that line while you are pumping at full rate, a jet pump is simple, serviceable and cheap to install. If the level can drop deeper, if the borehole is too narrow for an ejector body, or if you need high flow, a submersible is the correct answer — it pushes water up instead of pulling it.
Buyers routinely compare a jet pump and a submersible by quoting the static water level — the level when nothing is running. That is the wrong figure. What matters is the pumping level: how far the water surface falls in the well once the pump is running at its duty flow. This is the level the pump actually has to lift from, and it is always lower than static.
If you do not know it, it must be measured — during a drawdown test if possible. Sizing on the static level is the most common reason a “correctly sized” jet pump fails to reach pressure.
| Jet pump | Submersible | |
|---|---|---|
| How it lifts | Suction — pulls water up the pipe | Pushes water from below |
| Practical lift limit | About 7.5–8 m pumping level | Hundreds of metres |
| Efficiency | Lower — the motor runs at the surface, driving water through a jet | Higher — the motor is cooled by the flow and pushes rather than pulls |
| Noise | Audible; the pump sits in the house or a pump house | Near-silent at the surface |
| Service access | Easy — the pump is above ground | Requires pulling the pump and drop pipe |
| Freezing risk | Real, if installed in an unheated space | None — the pump is below the frost line |
| Best fit | Shallow wells, sand points, low flow, simple systems | Deep or narrow boreholes, high flow, year-round reliability |
Two variations matter here: a shallow well jet pump has the ejector built into the pump body and needs a single suction pipe, while a convertible jet pump puts the ejector down the well and uses two pipes (drive and suction) so it can work at greater depth. If your water level is marginal, the convertible arrangement buys you depth at the cost of extra plumbing.
The r/waterwell discussion on converting from jet to submersible is representative of how this usually ends: once a well is deeper than a jet can reliably serve, the submersible is the better long-term system rather than a luxury.
If you are replacing a jet with a submersible, budget for more than the pump:
Converting is usually worthwhile, but it is a system change and should be planned as one.
A shallow well jet pump that will not exceed about 40 psi. In the r/Plumbing thread on exactly this symptom, the pump had previously made 50 psi or more. That is a classic sign of a worn jet nozzle, a failing foot valve, or a suction line that has developed a small air leak — not of a pump that is “too small”.
A jet pump running continuously without building pressure. In the r/askaplumber case the pump had prime but still would not build pressure, which points at a recirculating ejector — a blocked or eroded nozzle letting water loop instead of lifting it.
Both are repairable. Both are also why jet systems should be configured with easy access to the ejector and foot valve.
Can a jet pump work on a well deeper than 8 m? A deep well jet (convertible) arrangement with the ejector down the well can serve greater depths, because the jet does part of the lifting work in the well. But the deeper you go, the more the system relies on a correctly matched ejector and the less efficient it becomes compared with a submersible.
Is a jet pump cheaper to run than a submersible? No — generally the opposite. A surface motor pulling water up is less efficient than a submerged motor pushing it, and the difference shows up on the electricity bill across the year.
Which one is better in freezing weather? The submersible, without question. It sits below the frost line. A jet pump in an unheated pump house needs freeze protection or it will be damaged.
How do I know my pumping level? Measure the water level with the pump running at full rate, not at rest. A drawdown measurement during a flow test is the reliable way; the static level will flatter the well.
Can I keep my existing pressure tank if I change pump type? Often you can, but the pre-charge and the switch settings usually need to change, and a tank sized for a jet pump’s cycle may be a poor match for a submersible’s different flow and cycling behaviour.
Which is better for irrigation? It depends on the source and the flow. For high-flow irrigation from a deep or narrow borehole, submersible. For a shallow well supplying a modest area, a jet pump is often adequate and simpler to maintain.
The wrong pump is usually the result of one missing measurement. Tell us your pumping level, required flow and available power and we will tell you which type fits — see our household water supply range, the surface and jet pump range, or our deep well and borehole range if the answer turns out to be submersible. If the numbers do not support a jet pump, we will say so.
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