How to Repair a Broken Well Pump

A well pump is an essential component of a water well system, used to draw water from underground and deliver it to your home. However, like any mechanical device, well pumps can eventually break down and require repairs. Knowing how to troubleshoot common well pump problems and perform basic repairs can save you the cost and hassle of calling in a professional. This article provides a step-by-step guide to diagnosing issues with your well pump and making necessary repairs to get it functioning properly again.

Understanding the Components of a Well Pump

Before diving into repairs, it helps to understand the basic components and operation of a well pump system. Here are the main elements:

  • Motor – Provides the power to operate the pump. Can be electric or run on gas or solar energy.
  • Impellers – Rotating blades that lift the water to the surface. Attached to the motor’s driveshaft.
  • Diffuser – Surrounds the impellers and prevents water from spinning backwards.
  • Shaft – Connects the motor to the impellers. Allows power transfer to the impellers.
  • Check valve – Prevents water from flowing back down into the well after being pumped up.
  • Pressure switch – Senses water pressure and turns the pump on or off as needed to maintain pressure in the system.
  • Pressure tank – Stores pressurized water and allows the pump to turn on and off at intervals rather than constantly run.
  • Piping – Carries water from the well to the pressure tank and into the home’s plumbing.

Diagnosing Common Well Pump Problems

When your well pump stops delivering water, there are some basic checks you can perform to identify the cause:

Pump Not Turning On

If the pump motor won’t start at all, the issue is likely with the power supply. Check that the breaker hasn’t tripped and reset it if needed. Ensure fuses are intact and wires are connected. Check voltage at the outlet with a multimeter. Contact an electrician if power supply components need replacement.

Pump Turning On But Not Pumping Water

If you can hear the pump motor running but no water comes out, it could indicate:

  • Dry Well – Very low water levels can prevent the pump from drawing water. Check static water level in the well.
  • Airlock – Pipes full of air rather than water. Briefly open faucets around house to let air escape.
  • Blockage – Something lodged in the pipes preventing water flow. Disconnect and inspect inlet/outlet pipes.
  • Broken Impeller – Impeller is worn or broken and not moving water. Impeller and diffuser need inspection.
  • Drop Pipe Disconnected – Rare, but pump components can become disconnected from drop pipe. Check unions and fittings.

Pump Cycles On and Off Frequently

If the pressure switch is turning the pump on and off more often than normal, the issue may be:

  • Leaky Plumbing – Listen for water running and inspect for leaks allowing pressure drops.
  • Malfunctioning Pressure Switch – Adjust settings or replace faulty switch if not turning on/off at proper pressure.
  • Undersized Pressure Tank – Smaller tank requires more frequent cycling. Upgrade to larger tank.
  • Waterlogged Pressure Tank – Internal membrane damaged causing waterlogging. Drain and replace tank.

Pump Turns On But Delivery Is Weak

A pump that lacks normal pressure and flow rate may indicate:

  • Worn Impeller – Impellers worn down from abrasive particles in water. Replace impeller.
  • Clogged Pipes – Sediment blocking pipes and reducing flow. Flush and clean piping.
  • Drop Pipe Scale Buildup – Mineral deposits restricting flow. Use scale remover and flush pipes.
  • Motor Wear – Bearings, brushes, or windings wearing down. Motor may need professional service.

Accessing the Well Pump for Repairs

Before any well pump repairs can be made, you need access to the pump itself. Submersible pumps are housed down inside the actual well casing, which requires removal of the well cap. Follow these safe practices when removing your well cap:

Gather Necessary Equipment and Supplies

  • Adjustable wrench or well cap wrench to unscrew cap
  • Headlamp or flashlight to see down into well
  • Gloves and eye protection for safety
  • Rope long enough to reach pump (eg. 50 ft)
  • Container to set cap in to keep clean

Shut Off Power Supply

Locate the circuit breaker or fuse that powers the well pump and switch it OFF. Lock out the panel if possible to prevent accidental start while working.

Sterilize Equipment

Dip or spray equipment with a chlorine solution before placing down into the well to avoid contamination.

Loosen and Remove Well Cap

Place a container next to the well casing to set the cap in. Use your wrench to loosen the threads holding the cap. Once loose, finish unscrewing by hand and pull cap straight up to remove.

Inspect Condition of Well

Shine light down the well casing. Look for debris or damage. Check water level. Sound and smell for anything abnormal.

Lower Rope and Secure Pump

Tie rope to handle on pump motor. Slowly lower until rope stops – do NOT let rope slip and drop pump. Tie off rope to secure pump from falling while working.

With pump access gained, you can now proceed with assessing and repairing the well pump system.

Troubleshooting and Replacing a Submersible Well Pump Motor

The electric motor is the heart of a submersible well pump. If the motor is not working properly, determining the specific problem is key to getting your water flowing again:

Check Voltage at the Motor

Use a multimeter to check voltage where the motor wires connect to the electrical line. If no power here, trace wiring back to find interruption.

Test for Electrical Shorts

Set multimeter to Ohms setting. Check resistance across motor windings. Very low or no resistance indicates a short. Inspect for damaged wires.

Assess Air or Water in Motor

Listen closely to running motor. Bubbles or water sloshing indicate a damaged motor housing. Replace seals and bearings or full motor.

Evaluate Sounds and Vibration

Unusual noise like scraping indicates damaged bearings. Knocking or rattling can mean broken motor parts. Have motor professionally evaluated.

Check Motor Resistance

Using multimeter, measure resistance across motor windings. Compare to factory specifications. Worn carbon brushes alter resistance.

Test Motor Capacitor

Use capacitor tester to check microfarads. Weak starting or running suggests bad capacitor. Only replace with exact microfarad value.

If diagnosis confirms the motor itself is damaged or non-operational, replacement will be required. Follow standard safety procedures and use equipment rated for well pump motor extraction.

Isolate and Disconnect Motor Electrical

Unhook wiring from defective motor to discharge. Tape off any exposed wires.

Rig Removal System

Attach pipe wrench grips, hoist hook, and retrieving line to raise motor up the well. Support full weight at all times.

Slowly Extract Motor

Progressively crank winch or pulley system to steadily draw motor up well casing. Have assistant guide outgoing motor.

Inspect and Replace Components

Once removed, thoroughly clean and lubricate shaft. Replace worn seals and bearings. Inspect housing, wires, and connections.

Lower New Motor

With power still off, reverse process to carefully lower repaired or new motor back into well casing until properly seated.

Reconnect Wiring

Attach wiring to proper motor terminals. Double check connections are tight and insulated before restoring power.

With the well pump motor replaced and restored to operation, turn power back on and test functionality before capping well. Monitor closely the first days to ensure proper performance.

Replacing a Submersible Pump Impeller

The rotating impeller blades are what push water to the surface. Gradual wear or sudden damage can stop the impeller and lead to pump failure. Here is how to remove and replace a submersible pump impeller:

Remove Pump for Access

Follow well access steps above. Secure pump so it safely hangs vertically while working on impeller replacement.

Unbolt Diffuser for Access

Locate bolts affixing diffuser. Use appropriate socket wrench to fully loosen and remove bolts. Set aside carefully.

Extract Impeller Assembly

With diffuser detached, the impeller should slide off the pump shaft. Carefully work assembly loose and lift out of pump housing.

Inspect and Replace Impeller

Examine old impeller for cracks, pitting, or erosion. Test shaft seat for wear. Obtain exact OEM impeller as replacement.

Reinstall New Impeller

Gently slide new impeller assembly onto pump shaft. Be sure it is fully seated. Reinstall diffuser and tighten mounting bolts.

Double Check Rotation

Briefly turn on pump to verify impeller is rotating correctly before returning down well. Make adjustments as needed.

Once confirmed that the new impeller is properly installed and rotating, you can lower the repaired pump back into the well casing and return to service.

Fixing Problems with Well Pump Piping

The above-ground portion of the well system includes important piping, valves, and tanks prone to their own set of issues. Here is how to troubleshoot and fix common problems with well pump piping:

Listen for AirSounds

If you hear air whooshing in the pipes, it indicates an airlock or improperly primed system. Let air out of faucets and retry priming process.

Inspect for Leaks

Walk along all accessible pipes and joints. Look for wet spots or dripping. Tighten fittings or replace leaky sections of pipe.

Check Pipe Condition

Feel along piping for cool or frozen sections that may indicate cracks under the surface. Repair or replace suspect areas.

Clear Out Sediment

Partially close valves and systematically backflush sections of pipe to force out collected sediment or scale.

Replace Corroded Sections

Look for green corrosion or pitting – signs of damaged galvanizing. Cut out and replace any visibly corroded sections.

Drain Waterlogged Tank

If tank remains full even with power off, membrane is damaged. Empty tank, disconnect piping, and install new tank.

Adjust Pressure Setting

If pump cycles too rapidly, pressure setting may be too low. Turn dial on pressure switch incrementally higher until cycles normalize.

Performing Routine Well Pump Maintenance

To maximize the life and performance of your well system, follow these proactive maintenance practices:

Annually Inspect Above-Ground Components

Check piping, wiring, tank, and pressure switch for damage. Tighten connections. Lubricate motor if needed.

Periodically Treat Well and Pipes

Shock chlorinate well to control bacteria. Descale pipes to prevent mineral buildup.

Regularly Test Water Quality

Have water sampled to check for bacterial and mineral changes needing treatment.

Every 5-10 Years Pull and Inspect Pump

It’s good practice to fully extract pump, replace seals and bearings, check shaft, and clear sediment from well bottom.

Listen for Changes in Operation

Be attentive to any sounds or performance changes that may indicate need for service.

Keep Spare Parts on Hand

Inventory consumable parts like piping, pressure switch, tank components to allow swift repairs when needed.

With proper well pump care and maintenance, you can maximize the lifespan and avoid unexpected breakdowns of this vital system. Learning to conduct basic troubleshooting and repairs yourself will keep you from waiting days for a service call. But for complex diagnoses or electrical issues, always contact a qualified well professional. Following the steps in this article will help you reliably deliver clean, fresh well water to your home for years to come.

Frequently Asked Questions About Repairing Well Pumps

Repairing a well pump on your own can be complicated without the right guidance. Here are answers to some frequently asked questions about diagnosing and fixing common problems with residential well pumps:

How can I test my well pump pressure switch?

  • Turn off power and drain pressure from the system. Remove switch cover and locate terminals. Check for corrosion. Set multimeter to Ohms setting and check continuity between terminals as pump pressurizes and depressurizes system. Reading should change from zero to high resistance at cut-in and cut-out pressure points. If not, adjust or replace switch.

What causes my well pump to cycle on and off frequently?

  • Frequent cycling usually indicates loss of pressure. Check for leaks in plumbing allowing air or water loss. Make sure tank is sized appropriately and undamaged. Inspect piping for blockages. Ensure pressure switch cut-in and cut-out settings are properly calibrated.

Why does my pump run but not deliver any water?

  • Common causes include airlock in pipes, clogged foot valve or inlet screen, broken or worn impeller, or pump not fully submerged in water. Prime system to remove air pockets. Clean or replace intake components. Check impeller operation and water level.

How do I know if my well pump motor is bad?

  • Warning signs include loud noise or vibration, reduced flow and pressure, tripping of electrical overload protector, overheating, shorts in winding insulation. Check voltage, resistance, capacitor, and take vibration readings. Compare to manufacturer specs to determine if replacement is needed.

What should I do about sediment in my water after replacing a well pump?

  • Replacing a faulty pump often stirs up sediment in the well. Let water run until clear. Use a whole house sediment filter. Consider periodic well chlorination or hydrofracturing to control sediment long-term. Always disinfect components before placing down well.

Is it worth repairing an old well pump or better to just replace?

  • Assess repair costs in parts and labor compared to replacement pump cost. Repair if issues are minor like worn impeller or leaky seal. But replacement may pay off long-term for major issues like damaged motor or corroded pipe.

How often should a submersible well pump be serviced?

  • No set service interval, but check amp load annually and pull pump to inspect every 5-10 years. Replace bearings, seals, pipes as needed. More frequent extraction if pumping sandy or silty water. Listen for changes in sound indicating need for service.

Why does my well pump cycle when no water is being used?

  • This often means loss of pressure through small leaks, valves left open, backsiphonage, or pressure tank issues. Inspect system for leaks. Close any valves. Check tank air charge and membrane. Adjust pressure settings if necessary.

What are signs my well pump pressure tank is failing?

  • Failure signs include waterlogged tank, air bubbles in lines, rapid cycling on/off, pump running continuously. Drain tank – if it doesn’t fully drain, replace tank. Check for leaks wet spots. Listen for pumping sound when water not in use.


Repairing a well pump requires methodical diagnosis, proper equipment, and attention to safety. While not overly complex for most do-it-yourselfers, be ready to call a professional if electrical, contamination, or complex mechanical issues exceed your skill level. Regular maintenance and monitoring will provide the best assurance of reliable water delivery from your well system.