Submersible Well Pump Problems and Repair

Likely causes

1. 1

   Cause 1: No power reaching the pump

   A tripped breaker, a blown fuse or a burned pressure switch contact stops the pump cold. Goulds lists an open breaker or blown fuse as a cause of a motor that won't run. Reset the breaker once. If it trips again right away, stop. That points to a short in the wire, the splice or the motor, and our page on a well pump tripping the breaker goes through it.

2. 2

   Cause 2: Thermal protector tripped

   Submersible motors have an overload that shuts them off when they get too hot. Goulds lists the causes: the wrong control box, bad connections, low voltage, a control box sitting in a hot spot, debris binding the pump, or the pump not being far enough under water. Many reset on their own once the motor cools. A pump that runs, quits, and starts again later is often doing exactly this.

3. 3

   Cause 3: A waterlogged pressure tank

   This is a common pump killer. When the tank loses its air cushion, the pump starts and stops every few seconds. Boshart lists rapid switch clicking, short cycling, a fluttering gauge and pulsing pressure as the signs, and warns that a waterlogged tank will burn out the pump. Fix the tank and you may save the pump. See waterlogged pressure tank.

4. 4

   Cause 4: A failed control box or capacitor

   Three-wire submersibles have a control box near the tank that holds the start capacitor and relay. When one of those fails, the motor hums or won't start. It's a surface repair. HomeAdvisor puts a start capacitor at $100 to $150 installed and a control box at $200 to $500. Two-wire pumps have the starting parts inside the motor, so there's no box to check. Our control box and capacitor page shows how a pro tests them.

5. 5

   Cause 5: A leaking check valve

   The check valve keeps water from draining back down the well when the pump shuts off. When one leaks, pressure bleeds off with every tap closed and the pump kicks on for no reason. Boshart notes that water hammer is often the cause of system failure, and that backflow can damage the pump. A failed valve down the well means a pull.

6. 6

   Cause 6: Air-bound pump or gas in the well

   Goulds lists an air-bound pump as a cause of little or no water, and suggests starting and stopping the pump several times until water flows. If that doesn't help, the well probably has excess air or gas in it. Spitting faucets point here too; see air in water lines on a well.

7. 7

   Cause 7: Worn pump or sand damage

   Sand chews up impellers. Boshart says pumping sand can rapidly destroy a pump and plumbing fixtures, and that submersibles normally sit at least 10 to 20 feet above the well bottom to stay clear of it. A pump that runs but delivers less and less water every month is usually worn. Goulds lists excessive pump wear among the causes of low flow, and the fix is to pull and repair.

8. 8

   Cause 8: Low water level or a dry well

   If the water drops below the pump, it pulls air and overheats. Goulds says motors need at least 5 feet of water over them. Low output in late summer, or water that comes back after a rest, points to the well rather than the pump. See no water from your well.

9. 9

   Cause 9: Damaged wire or a bad splice

   The wire runs down the casing to a splice at the motor. Goulds lists damaged cable insulation and a faulty splice among the reasons a motor won't run. This shows up as a tripping breaker or a pump that works some days and not others. It means pulling the pump.

10. 10

    Cause 10: A dead motor

    After everything else, the motor itself can fail from age, heat or lightning. HomeGuide puts a well pump's life at 10 to 15 years with proper care. A motor that's near that age and fails a resistance test usually gets replaced along with the pump end.

Checks you can do safely

With the breaker off unless noted:

• Look at the breaker. Off or in the middle? Reset once.
• Watch the pressure gauge while someone runs a tap. Does it drop and the pump never start? That points at the switch or power. Does the needle flutter while the pump clicks on and off? That points at the tank.
• Close every tap and watch the gauge for a few minutes. If it drops with nothing running, you have a leak or a leaking check valve.
• Knock on the upper half of the pressure tank. Boshart says it should sound hollow, and a solid sound means it's full of water.
• Look at the control box, if you have one, for scorch marks or a swollen capacitor. Don't open it with the power on.
• Run a faucet into a clear glass. Sand or grit settling out means the pump is pulling sediment.

Fixes

Some pumps are best protected after the fact. Franklin's Pumptec cuts power to the motor when the load drops off, guarding against dry wells and waterlogged tanks. It's worth asking about on a well that runs low.

When to call a pro

Call a licensed well contractor when the breaker trips again after one reset, the pump hums but won't start, the pump runs but water doesn't come, sand shows up, or the pump has to come out of the well. Pulling a submersible is heavy, two-person work with a wet electrical splice at the bottom, and a dropped pump can block the well.

HomeAdvisor puts the average well pump repair at $974, with most falling between $373 and $1,624. Expect a house call fee of about $100 to $150. For a full replacement, our well pump replacement cost page breaks down the bill.

Maintenance that keeps a submersible alive

There's nothing to grease on a submersible. What you can do is protect it. Keep the pressure tank's air charge right, replace a sticking gauge so you can trust it, and fix leaks so the pump isn't cycling all day. HomeGuide recommends a well inspection every 1 to 2 years.