Do submersible pumps lose prime?

No — priming is a jet-pump issue. Submersible pumps sit underwater and push rather than suck, so they do not need priming. A check-valve problem can still cause other symptoms.

Why does prime hold for a while then disappear?

That pattern often points to a foot valve or check valve letting water drain back after the pump stops. An air leak, by contrast, usually prevents prime from holding at all.

Well Pumps

Well Pump Keeps Losing Prime: Causes and Fixes

A jet pump that keeps losing prime has air getting into the suction side. Here are the usual culprits and why repeated priming is a warning sign.

By Know Your Well Water Editorial TeamReviewed October 29, 20262 min read

Quick Answer

Losing prime means a jet pump has lost the water it needs in its suction side, so it spins but moves air instead of water. The usual causes are an air leak in the suction line, a failed foot valve or check valve letting water drain back, or a water level that has dropped. Repeatedly re-priming without fixing the cause stresses the pump and often means it is running dry.

Why prime matters

A jet pump works by suction, which only works if the pump and its suction line are full of water. If air gets in — or water drains back into the well between runs — the pump loses that water column and can no longer pull from the well. A foot valve or check valve is supposed to hold the water in place; when it fails, prime leaks away.

Common causes

An air leak at a fitting, joint, or seal on the suction side.
A failed foot valve or check valve letting water drain back into the well.
A cracked suction pipe.
The water level dropping below the intake so the pump draws air.
A worn pump seal.

Running dry is harmful

A pump moving air instead of water can overheat quickly. If re-priming does not hold, do not keep running the pump dry — the cause needs to be found.

What usually fixes it

Diagnosing lost prime

1Inspect visible suction-side fittings and joints for leaks or loose connections.
2Note whether prime holds briefly then fails (often a valve) or never holds (often an air leak).
3Have the foot valve or check valve checked — a failed one is a frequent culprit.
4If the water level has dropped, a professional can assess the well and pump depth.

Deeper fixes are a pro job

Replacing a foot valve down the well, repairing the suction line, or any work near energized components should be done by a licensed professional. Reset a tripped breaker only once.

Frequently asked questions

Do submersible pumps lose prime?: No — priming is a jet-pump issue. Submersible pumps sit underwater and push rather than suck, so they do not need priming. A check-valve problem can still cause other symptoms.
Why does prime hold for a while then disappear?: That pattern often points to a foot valve or check valve letting water drain back after the pump stops. An air leak, by contrast, usually prevents prime from holding at all.

Sources & references

Protect Your Home’s Water: Private Wells — US EPA, accessed October 29, 2026

This guide is documentary research and general information, not a laboratory analysis or professional assessment of your specific well. See our disclaimer.