Informational Guide

How To Prime A Well Pump

Follow our step-by-step guide where we show you how to prime a well pump correctly & what you can do if your pump won’t prime properly.

by Josh Mitchell

Well pumps have been used for thousands of years to provide a fresh supply of clean water. You may not realize it, but wells are still used by millions of people worldwide, but these days it’s all mechanical and electrical.  

Well pumps are used to drive the water up from deep underneath the ground into your home. They work pretty effortlessly, but you need to make sure there’s enough pressure so that the water can rise up the pipes and into your storage tank.  

This guide will show you how to prime a well pump so that there’s enough pressure in the pipes to give you ready access to clean water.  

A well pump is an old-school way of getting water into your home. A hole is dug down into the earth to give you access to your water supply, and piping is fitted with an electrical pump that draws the water out and allows it to flow into a storage tank. This then allows you to access the clean water from within your home.  

There are a couple of types of well pumps, and each uses a different method to give you access to clean water. Here’s a quick breakdown: 

Centrifugal Pump 

Centrifugal pumps are pretty common and the most affordable type of well pump. They use a fan to create suction which then forces the water to rise through the pipes. The mechanism for a centrifugal pump sits next to the well in a separate housing unit.

This makes it easier to clean and maintain the mechanism without disrupting the pipes. Centrifugal pumps only have enough power for shallow wells and shouldn’t be used on anything below 25 feet.  

Submersible Pump 

This well pump is the most common on the market because it gives a great deal of flexibility. Submersibles operate from underwater within the well. The watertight pumps use motor impellors to force the watch up the pipes and into your tank.  

The pump itself won’t work unless it's totally submerged, allowing it to turn off automatically when the watch runs low. These types of well pump are suitable for shallow or deep wells but can be tricky to repair. You’ll need to pull the whole pump out of the water so that a technician can get to work on it. 

Jet Pump 

Jet pumps are the most expensive option which provides the most power. There are two types of jet pumps, single-drop or double-drop. Single-drops are used for shallow wells, and the mechanism is housed outside of the well.  

Double-drops are used for deep wells with a split mechanism, the motor is above ground, and the jet is within the well. A jet pump is used to force the water up with a great deal of force, giving you water much faster than alternative types of well pumps and give you the best pressure.  


Why Priming a Well Pump Is Necessary? 

Priming your well pump is essential if you want it to run correctly. Priming is the process of manually creating a vacuum in your pump so that water can be pulled through your pipes and into your storage tanks. You will need to do this when the pump is first installed and if there are any sudden dips in pressure. 

There are two main types of well pump, submersible and non-submersible. Submersible pumps are used for deeper wells and generally won’t need to be primed because they operate completely underneath the water.  Non-submersible pumps are used for shallow wells and need to be primed more often, particularly during installation.  

How To Prime A Well Pump

How To Know A Well Pump Needs Priming 

When your well pump loses pressure, it will probably need to be primed. There are a few key reasons why this happens: 

  • Water Level Too Low 
    If your water level is too low, then it means you've drawn up too much water, and there literally isn't enough for you to draw. You may need to leave the pump for a few days to let the water level rise again.  
  • Leak In Water Lines 
    If there’s a leak in your water lines then water, and air can escape, and the vacuum is broken. This means there will be insufficient pressure to allow your water to pump upwards, and you’ll have to reprime the pump to get it working.  
  • Failing Check Valves 
    Check valves are used to keep some water in the intake valve even when the well pump isn’t in use, allowing the pressure to be maintained. If your check valve fails, then the water will drop down the pipe, and you'll lose your prime.  
  • Air Gaps In Intake Pipes 
    Any air gaps in your intake pipes will break the vacuum and prevent the water from being drawn upwards. You’ll need to fix these or replace the pipe before repriming.  
  • Drawdown From Hose Or Tap Left Running 
    If water is continually drawn from the pump, then the pressure will drop. A leaky tap or faucet is usually the leading cause, and you'll need to fix this before repriming.  

How To Prime A Well Pump (Step-By-Step Guide) 

A well pump needs to be primed so there’s adequate suction to allow the water to be drawn upwards. The majority of well pumps are self-priming, which means they create a partial vacuum in the pipe, which draws water upwards. For this reason, you’ll probably only need to prime your pump during installation. 

Here’s a guide of how to do it: 

Steps For Priming a Well Pump 

  • 1
    Shut Off The Pump 
    Completely disconnect the well pump from the electrical outlets.  
  • 2
    Check The Pump 
    Check for any visible damage, cracks, or other issues which might impact the pump's functional ability.  
  • 3
    Remove The Prime Plug 
    This is usually located on the head of the plug and should be simple to remove.  
  • 4
    Open The Release Valves 
    This will stop the pressure from building up within the pump. 
  • 5
    Attach A Hose 
    Clean out a hose and attach it to the pump. Make sure there’s no lead or other contaminants in your hose. 
  • 6
    Run The Water 
    Keep running water through your pump where the prime plug was. Keep it running until the pump starts to overflow. Remember, the water you use at this point should match the type of water you’ll be drawing. If it is pumping drinking water, then make sure you use drinking water for this stage.  
  • 7
    Replace The Prime Plug 
    Replace the prime plug and reconnect the pump to the power source. If it’s all working normally and cycling correctly, then you've done the job. If not, then repeat these steps until it starts working.  

Jet pumps are designed to draw water from very low depths. To do this, they have two sets of pipes, one for suction and one to direct water towards your outlet. To prime a jet pump, you will need to follow all the steps above, but make sure you run water through both pipes.  

You can find a full video guide on how to prime your well pump below. 


Priming Variations 

Shallow Well Pumps

Shallow well pumps are not submerged, which means they need to be primed when they’re first installed. You can do this by following the steps above. Sandpoint wells operate in depths of less than 25 feet and need to be primed to work effectively. 

You’ll need to open up the check valve and fill it with water so that the pressure can be maintained in the pump, allowing water to be pumped to the surface.   

How To Plumb A Shallow Well Pump

Well Pump with Pressure Tank 

Pressure tanks are used to help keep the pressure in your water consistent so that when you turn on a tap, shower, or other outlet, it's always the same. To prime a well pump with a pressure tank, you’ll need to follow all the steps above, but make sure you open up the valve on the pressure tank itself to remove any air. This will allow you to pressurize the whole pump, not just one part of it. 

After a Water Outage 

If your water goes off unexpectedly, your water will lose its pressure and need to be reprimed. Following the steps above should work; just make sure you flow enough water through the pump until it cycles correctly. You may need to repeat the process 3-4 times before it works correctly.  


What To Do If Your Well Pump Is Losing Prime? 

If your well pump is starting to lose its prime, there's a couple of things you should look out for:  

  • Check For Leaks 
    The majority of the time, if your pump is losing its prime, then it's because of a leak on the intake pipe. Check the pipe, the seal, and the shaft for any visible leaks, and make sure it’s all fitted tightly.  
  • Check For Faulty Valves 
    Foot valves are used to keep your water in the intake line when the pump isn’t operating. If this is faulty, then the pressure will drop, and it will lose its prime. If this is the issue, you will probably be able to replace the valve. 
  • Check For Blockages 
    Blockages in the line caused by debris can cause the well pump to lose its prime. By turning off the system and running high-pressure water through the device, you can help to remove these blockages.  

People also Ask (FAQs)

Does the pump lose its prime when turned off? 

No, your pump shouldn’t lose its prime when turned off and if it does, it could mean there's a leak somewhere in the system.  

What happens if you don't prime your well pump? 

Without a primed well pump, you won’t have any water flow because the water won’t be drawn up the intake pipe. 

How long does it take a well pump to prime? 

It only takes a few minutes to prime your pump and a few more minutes on either side to disconnect and reconnect it.  

How much water does it take to prime a well? 

It will typically take a couple of gallons of water to prime a well pump.  

How do you prime a Goulds Jet Pump? 

You can prime a Goulds jet pump using the instructions above, but you need to: 

  1. 1
    Completely turn off the power 
  2. 2
    Remove the casing and the vent plug  
  3. 3
    Pour running water into pump until water comes from the vent hole where the plug was 
  4. 4
    Reattach the vent plug, top off water at the gauge and put the casing back on 
  5. 5
    Turn the power back on 
  6. 6
    Open faucet pump to remove air from system 
  7. 7
    Repeat as needed 

Conclusion

Well pumps are the modern solution to an age-old problem, and most of the time, they run without a glitch. They must be primed, so there's enough pressure to allow water to be drawn, but thankfully it isn't too difficult to prime a well pump yourself.

Hopefully, this article has given you some useful information about when you need to prime your pump and given you the confidence to prime it yourself.  

Josh enjoys researching, testing and diving into home improvement & DIY products. He has a passion for tools, learning new skills and fixing the everyday problems that arise around the house.

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