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How to Prime Your Borehole or Wellpoint Pump
Priming is one of the most important checks for a surface pump that has stopped drawing water. Done correctly, it removes trapped air and helps the pump build the suction it needs to work properly.
One point matters up front: not every pump is primed the same way. A submersible borehole pump sits below the water level and is not typically primed like a surface wellpoint pump. In most cases, this guide applies to surface-mounted pumps used with wellpoints, tanks, and some suction-based water systems.
Why priming matters
A pump cannot create proper suction if the casing and suction line are full of air. Priming fills the pump with water before startup so the system can begin drawing water correctly. It also reduces the risk of dry running, overheating, and premature wear.
What you need
- A clean water source such as a hose or container
- A combination spanner or plumber's pliers
- PTFE tape if the priming plug needs resealing
Step-by-step priming process
Step 1
Switch the power off
Turn the pump off before touching any fittings. This prevents electrical risk and stops the pump from running dry while you work.
Step 2
Find and remove the priming plug
Locate the priming plug on the top or side of the surface pump housing. Use a spanner or pliers to loosen it carefully.
Step 3
Fill the pump housing with clean water
Pour water slowly into the priming opening until the pump casing is completely full. If the level drops, keep topping it up so trapped air can escape.
Step 4
Refit the priming plug securely
Replace the plug firmly so the system does not draw air. If the seal is worn, apply fresh PTFE tape before tightening it.
Step 5
Start the pump and let it build suction
Switch the pump back on and monitor it closely. Keep the discharge side controlled and watch for pressure building and water flow stabilising. Do not let the pump run for long without water.
Step 6
Stop and retry if it does not pick up water
If the pump still sounds hollow, fails to build pressure, or loses prime quickly, switch it off and repeat the process. Persistent problems usually point to an air leak, blocked suction line, faulty foot valve, or another mechanical issue.
Important safety notes
Never allow the pump to run for an extended period without water in the casing.
Do not keep valves fully closed in a way that strains the pump for too long while it is running.
If the pump repeatedly loses prime, the issue is usually not the priming itself. It is often a leak, blockage, faulty valve, or a worn part somewhere in the system.
FAQs
Can a borehole pump be primed?
Usually no. A submersible borehole pump operates underwater and is not primed in the same way as a surface pump. Priming applies to surface-mounted pumps such as many wellpoint and booster pump setups.
How often should I prime a pump?
Normally only during first installation, after maintenance, or after the system has lost prime. If you need to prime often, there is likely an underlying fault that should be checked.
What are signs the pump is not properly primed?
Common signs include a hollow sound, weak or no water flow, pressure that does not build, or the pump running without drawing water.
What causes a pump to lose prime?
The usual causes are air leaks on the suction side, a leaking fitting, a damaged seal, a faulty non-return or foot valve, or a blocked intake line.
When should I call a professional?
If the pump still will not pull water after careful priming, or if you suspect an electrical, suction-line, or pressure issue, it is best to have the system inspected professionally before damage occurs.
Need help with a pump that still will not prime?
If your wellpoint or surface pump still is not pulling water after priming, the system may need a proper inspection. Faults on the suction side can quickly lead to poor performance or pump damage.