Bore pumps: what they are and what goes wrong
A bore is a hole in the ground with a pump at the bottom. Most of the trouble starts with what nobody measured before the pump went in.
A bore pump is not just a tank pump that goes down a hole. The pump has to lift water from depth, cope with sand, and survive being out of sight. The most important number is one you may not have: the standing water level and the yield of your bore.
The two main types
- Submersible bore pump. A long, narrow motor and pump that sits down the casing under the water. It pushes water up the pipe, and it is the common choice for deeper bores.
- Surface pump. Sits at ground level and pulls water up a suction line. It only works where the water is close to the surface, because suction has a physical limit.
Deeper than a few metres to water, and a submersible is normally the only workable answer.
What decides the pump you need
Three things, in this order.
Depth to water. How far the pump has to lift, and how far the level drops while it is running.
Bore yield. How much water the bore can supply without emptying. A pump that moves more than the bore yields will run dry and burn out. This is the fault behind a great many dead bore pumps.
What the water is for. Watering a garden is forgiving. Feeding the house is not, and the pump then needs pressure control and often a tank between the bore and the fixtures.
Common faults
Runs but no water. The water level has dropped below the pump, the intake screen is blocked. Or the pump has lost its prime if it is a surface unit.
Sand in the water. Sand wears out impellers fast and it can clog fixtures. It often means the bore casing or screen has failed, and that is a driller question, not a pump question.
Cycles on and off. Often a pressure vessel or pressure switch problem, or a bore that cannot keep up with the pump.
Trips the power. A wet motor, a failing cable joint or an overload. Do not handle this yourself.
Bore water is not automatically safe
Water from a bore should never be assumed fit to drink. Only an accredited (NATA) laboratory can tell you what is in it, and bores can carry salts, iron, bacteria and other contaminants. See water quality before it goes anywhere near a kitchen tap. Many states also regulate bore drilling and extraction, so check with your state or territory authority before you commission one.
Where DIY stops
Pulling a pump from a bore means heavy gear, live electrical connections and a real chance of dropping it down the hole. The wiring is electrician work. Connecting bore water to the house is plumbing work. Compare the tank-side options in water tank pumps.
Bore pump symptoms and the first thing to check
Most bore pump problems show up as one of four symptoms. Use this table to find the likely cause and the right person to call.
| Symptom | Likely cause | First check | Who handles it |
|---|---|---|---|
| Runs but no water | Level below the pump, blocked intake screen, or lost prime on a surface unit | Listen for the pump running and note whether any water arrives | Pump supplier or driller |
| Sand in the water | Failing bore casing or screen | Fill a clear glass and look at what settles | Driller, not the pump supplier |
| Cycles on and off | Pressure vessel or switch fault, or a bore that cannot keep up | Note how often it cycles | Licensed plumber |
| Trips the power | Wet motor, failing cable joint or overload | Nothing. Do not handle it | Licensed electrician |
| Pump dies after a dry spell | Pump moving more than the bore yields | Ask what the bore yield is | Driller and pump supplier |
Check also the tank pump guide if your pump moves water from a tank rather than a bore.
What to find out before you talk to a pump supplier
A supplier can only size a pump if you can answer a few questions. Gather these first, and the quote will be better.
- Depth to water. This is how far the pump has to lift, and how far the level drops while it runs.
- Bore yield. This is how much the bore can supply without emptying. A pump that moves more than the bore yields will run dry and burn out.
- What the water is for. A garden is forgiving. Feeding the house needs pressure control and often a tank between the bore and the fixtures.
- Water quality. Bores can carry salts, iron and bacteria, and the water should never be assumed fit to drink. Ask about a laboratory test.
- Local rules. Many states regulate drilling and extraction, so check with your state or territory authority before you commission anything.
- Who does the wiring and the plumbing. Wiring is electrician work and connecting bore water to the house is plumbing work.
Hand the supplier your answers in writing. If they will not ask about depth and yield, find another supplier.
Frequently asked questions
What is the difference between a bore pump and a tank pump?
A bore pump lifts water from underground, often from depth, and has to handle sand and variable yield. A tank pump moves stored water at a short distance. The two are built and sized differently.
Why does my bore pump run but deliver no water?
The most common causes are a water level that has dropped below the pump, a blocked intake screen, or lost prime on a surface pump.
Why is there sand in my bore water?
It usually points to a failing bore screen or casing rather than the pump. Sand wears impellers quickly, so get the bore assessed by a driller.
Is bore water safe to drink?
Never assume so. Only testing at an accredited NATA laboratory can tell you what is in it.
Sources
What this page explains is based on these official sources. If you check one and it does not match what you read here, send it to us and the article gets corrected.
- NHMRC. Australian Drinking Water Guidelines
- Australian Building Codes Board. National Construction Code — Volume Three (Plumbing Code of Australia)