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Fix a jet pump that loses prime

We'll check the foot valve, suction line leaks, and well level—then fix or replace—or tell you when to call a pro.

Troubleshooting · Home maintenance
20–45 min
What you'll need
  • Water (for priming)
  • Wrenches and pipe tools
  • Replacement foot valve (if needed)
Step 1 of 7

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Steps

Goal: Confirm the symptom, then check the foot valve and suction line.

  • Run the jet pump. It works. Stop it. Start again—it needs repriming.
  • Good: Loses prime—foot valve or leak. Proceed to Check foot valve.
  • Bad: Holds prime—problem may be intermittent.

Check foot valve

Goal: Replace the faulty foot valve if accessible.

  • The foot valve holds water when the pump stops. A faulty one lets water drain. If accessible, replace it. If in the well, call a pro.
  • Good: Foot valve replaced. Proceed to Check for leaks.
  • Bad: Foot valve in well—call a pro.

Check for leaks

Goal: Rule out air leaks in the suction line.

  • Inspect the suction line and fittings. Tighten loose connections. Check for cracks.
  • Good: Leak found and fixed. Prime and test.
  • Bad: No leak—check well water level; call a pro if low.

When to get help

Call a well or pump professional if:

  • The foot valve is in the well and you cannot access it.
  • The well water level is low.
  • You cannot find the leak.

Verification

  • Pump delivers water when started without repriming.
  • Pump holds prime when it stops.
  • No air bubbles in the suction line.

Escalation ladder

Work from the device outward. Stop when the problem is fixed.

  1. Confirm symptom Verify the pump loses prime when it stops.
  2. Check foot valve Replace the foot valve if faulty and accessible.
  3. Check for leaks Inspect suction line and fittings for air leaks.
  4. Check well level Confirm water level stays above the foot valve.
  5. Call a pro Foot valve in well or low well level—call a professional.

What to capture if you need help

Before calling support or posting for help, have these ready. It speeds everything up.

  • Pump type and well depth
  • Suction line condition
  • Steps already tried

Does the jet pump lose prime when it stops?

Pump works when running but needs repriming after it stops.

Run the pump. Stop it. Start again. Good: needs repriming—foot valve or leak. Bad: holds prime—problem may be intermittent.

Yes No

You can change your answer later.

Is the foot valve faulty or inaccessible?

The foot valve holds water when the pump stops. A faulty one lets water drain.

If the foot valve is accessible (shallow well), replace it. If it is in the well, call a pro to pull the pipe. Good: foot valve replaced. Bad: foot valve in well—call a pro.

Yes No

You can change your answer later.

Are there leaks in the suction line?

Air leaks prevent holding prime.

Inspect the suction line and fittings. Tighten loose connections. Good: leak found and fixed. Bad: no leak—check well water level.

Yes No

You can change your answer later.

Is the well water level above the foot valve?

Low well level can cause the suction line to drain.

If the well water level drops below the foot valve when the pump is off, the line drains. You may need to lower the foot valve or add storage. Call a pro for well level issues. Good: level is fine—retest. Bad: low level—call a pro.

Yes No

You can change your answer later.

Prime and test

Prime the jet pump. Run it, stop it, wait. Start again. If it delivers water without repriming, the fix worked.

Done

Pump holding prime

The jet pump should now hold prime when it stops. Confirm it does not need repriming.

Done

Call a pro

Call a well or pump professional if the foot valve is in the well, the well water level is low, or you cannot find the leak.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why would a jet pump lose prime?
Common causes: faulty foot valve (water drains when pump stops), air leak in the suction line, or well water level dropping below the foot valve. The foot valve is the most common cause.
Can I fix a jet pump that loses prime myself?
Yes, if the foot valve is accessible. You can replace the foot valve and check for leaks. If the foot valve is in the well, a professional may need to pull the pipe.
When should I call a pro for a jet pump that loses prime?
Call a well or pump professional if the foot valve is in the well, the well water level is low, or you cannot find the leak.

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