Jet pump and shallow well service

A jet pump sits above ground and pulls water up from the well by suction, which is why it can lose prime and why a submersible cannot. Shallow well jet pumps are limited to about 25 feet of lift. Deep well jet pumps use a downhole ejector to reach further, commonly around 100 feet. Most repairs involve prime loss, the foot valve, or the pressure switch.

Jet pump versus submersible

	Jet pump	Submersible
Where it sits	Above ground, in a well house or garage	Down the well, underwater
How it moves water	Pulls by suction	Pushes from below
Can lose prime	Yes	No
Noise	Audible, sometimes loud	Silent to you
Depth limit	About 25 ft shallow, roughly 100 ft deep well	Practical to many hundreds of feet
Service access	Easy, it is right there	Requires pulling from the well
Efficiency	Lower	Higher

The one genuine advantage of a jet pump is access. When it fails you can see it, reach it, and work on it without a truck and a reel. That matters, and it is why plenty of older properties still run them.

Why prime is the recurring problem

Priming means the suction side of the pump is full of water with no air in it. A jet pump cannot pull water if it is trying to pull air.

Prime is lost when air gets in, and air gets in through:

• A failed foot valve. The valve at the bottom of the suction pipe holds water in the line when the pump stops. When it leaks, the line drains back down the well and the pump has nothing to grab on restart.
• A leak in the suction line. A crack, a loose fitting, or a bad seal anywhere between the water and the pump. These can be small enough that they never drip visibly, because that side of the line is under vacuum rather than pressure.
• A failed check valve at the pump.
• A dropping water level. If the water is now further below the pump than it can lift, the pump loses prime for a reason no repair to the pump will fix.

That last one deserves attention around here. Groundwater levels in the Chino Valley area have fallen for decades, with depth to water typically increasing 80 to 100 feet for a well drilled 50 years ago. A shallow well jet pump has almost no margin for that. See falling groundwater and what it means for your well.

Common jet pump repairs

Foot valve replacement. Requires pulling the suction pipe, which is far lighter work than pulling a submersible.

Suction line repair. Finding the leak is most of the job. A pressure test on the suction side locates it.

Pressure switch. Same part and same failure mode as on a submersible system.

Impeller or diffuser. Wear or debris damage reduces output. On some pumps these are replaceable, on others the pump gets replaced.

Seal replacement. A leaking shaft seal drips at the pump and eventually reaches the motor.

Motor. Bearings and windings fail with age. Whether to replace the motor or the whole pump depends on the pump’s condition and age.

When conversion makes sense

Converting from a jet pump to a submersible is worth pricing when:

• The water level has dropped past what the jet pump can lift
• The well is deep enough to set a submersible properly
• You are tired of losing prime
• The existing pump is at the end of its life anyway
• The noise is a problem, which it often is when the pump shares a wall with living space

It is worth not doing when the well is genuinely shallow, the jet pump is in good condition, and prime holds. There is no prize for replacing equipment that works.

A contractor should measure the static water level before recommending either direction. See well pump replacement for how sizing works on the submersible side.

Next step

Tell us what the pump is doing and we will connect you with an independent local contractor who works on jet pumps and shallow wells in the Prescott area. Start here.