The pump is the component that decides whether a borehole feels like an asset or a recurring problem. Choose it correctly and it runs quietly for years. Choose it on price or on someone's rule of thumb and you get short cycling, dry running, high running costs and a motor that fails early.
Borehole pump installation is a sizing exercise before it is an installation exercise. There is no such thing as a good pump in the abstract - only a pump that matches a particular borehole, a particular depth and a particular demand.
Replacing a failed pump or fitting a first one? Send the borehole depth and yield if you have it.
Get a Pump Installation QuoteHow a Borehole Pump Is Sized
Two numbers determine pump selection, and both have to be established before anything is ordered.
1. What the borehole can sustainably give
This comes from yield testing - specifically the sustainable abstraction rate and the pumping water level at that rate. A pump must never be sized to take more than the borehole can sustainably deliver. This is the most common and most expensive mistake in the whole field.
When a pump out-draws the formation, the water level falls toward the pump intake. The pump begins pulling air, loses its cooling flow, trips on protection if it has any, and burns out if it does not. The owner concludes the borehole has failed. Usually the borehole is fine.
2. What the pump has to work against
Total dynamic head is the sum of everything the pump must overcome, and it is measured in metres:
- Pumping water level - the depth to water while the pump is running, which is deeper than the resting level. This is the number that matters, not the standing level.
- Vertical lift above ground to the discharge point, including any elevated tank stand.
- Friction losses through the rising main and the distribution pipework. Longer runs and narrower pipe cost head, sometimes a surprising amount.
- Required outlet pressure where the water feeds a pressure system, irrigation with sprinkler or dripline requirements, or a building.
Only once you have flow rate and total head can a pump be selected from its performance curve. Every pump has a curve showing how much it delivers at each head, and the correct pump is the one whose curve passes through your actual duty point efficiently - not the one with the biggest headline figure on the box.
Bigger is not better. An oversized pump is worse than a slightly undersized one. It over-draws the borehole, runs outside its efficient range, cycles more, costs more to run and fails sooner. If in doubt, size to the tested sustainable yield and add storage to cover peak demand rather than reaching for a larger pump.
Setting the Pump Depth
Where the pump sits in the borehole matters as much as which pump it is:
- Deep enough to stay comfortably below the pumping water level under full load, with margin for seasonal decline
- High enough above the borehole floor to stay clear of accumulated sediment, which is abrasive and destroys impellers
- Positioned relative to the screened interval so water flows past the motor for cooling
- Not so deep that the pump is working against unnecessary head, which wastes energy on every cycle
- Recorded in writing, so that anyone servicing the borehole later knows what is down there and at what depth
A flow sleeve or shroud is sometimes fitted to force water past the motor for cooling, particularly where the pump has to sit above or level with the inflow.
What Goes Into a Pump Installation
| Component | What matters about it |
|---|---|
| Submersible pump and motor | Sized to the duty point from the pump curve. Multistage units are standard; the number of stages sets the head. |
| Rising main | Pressure class rated for the depth and pump pressure. Joints have to be secure - a failed joint drops the pump. |
| Submersible cable | Rated for permanent immersion and sized for both motor current and run length. Undersized cable causes voltage drop and overheating. |
| Cable joints | Properly made waterproof splices. A poor joint is one of the most common causes of premature motor failure. |
| Safety rope or line | Takes the weight of the pump for retrieval, so the rising main is never the lifting element. |
| Non-return valve | Holds the column of water and stops backspin on shutdown. Backspin damages pumps. |
| Control box or panel | Starting gear, overload protection and, on some units, capacitor and relay. |
| Dry-run protection | Level probe, current sensing or pressure sensing. The single most valuable safeguard on the system. |
| Isolation and headworks | Sealed cap, isolation valve, discharge connection and a pressure test point where possible. |
Not sure whether your existing pump is the right size? A yield test settles it before you spend on a replacement.
Request a Pump Assessment QuoteControls and Protection
Protection is not an optional extra on a submersible pump - it is what keeps a costly item out of a borehole you cannot easily reach.
- Dry-run protection stops the pump when the water level drops to the intake, before damage occurs.
- Overload protection guards the motor against excessive current from a jammed impeller or a failing bearing.
- Single-phase and phase-failure protection on three-phase installations, where losing a phase will destroy a motor quickly.
- Voltage protection against under- and over-voltage, which matters where supply is unstable.
- Float or level control where the pump fills a tank, so it stops when the tank is full and starts when it draws down.
- Pressure switch and vessel on a direct pressure system, with the vessel pre-charge set correctly to limit cycling.
- Variable speed or constant pressure control, which matches pump output to demand, reduces starts and holds steady pressure. It costs more upfront and suits some systems better than others.
Short cycling - starting and stopping repeatedly - is one of the main killers of borehole pumps. Most cycling problems trace back to a pressure vessel with the wrong pre-charge, a failed vessel bladder, a leaking non-return valve, or a pump that is simply too large for the demand it is serving.
Replacement Pumps
When an existing pump fails, resist the temptation to order the same model and drop it back in. That model may never have been right, and conditions may have changed since. Before replacing, it is worth establishing:
- 1Why it failed. Dry running, a burnt motor, worn impellers from sand, a cable or joint failure and a control fault all point in different directions and call for different remedies.
- 2What the current water level and yield are. Boreholes change over time. A pump that suited the borehole ten years ago may be over-drawing it now.
- 3Whether sand is present. Persistent sand means the pump was destroyed by an underlying construction or development problem that a new pump will not fix - see borehole rehabilitation.
- 4Whether demand has changed. Added irrigation, a pool or an extension changes the duty point.
- 5Whether protection was fitted. If the old pump had no dry-run protection, fit it now rather than replacing another pump in two years.
A failed pump is the best opportunity you will get to correct a sizing error, because the pump is already coming out of the hole.
Signs Your Pump Is Not Right for the Borehole
- Flow that starts strong and falls away after a few minutes of running
- The pump cutting out and restarting on its own during normal use
- Frequent short cycling, particularly on a pressure system
- Air spluttering at the outlet
- Sand or grit appearing in the water or collecting in filters
- Running current higher than the motor rating on the plate
- Motor failures recurring every couple of years
Several of these point to a system problem rather than a pump problem. The borehole repairs page covers diagnosis where a system is already misbehaving.
What Affects Pump Installation Cost
| Factor | Effect on price |
|---|---|
| Borehole depth | Sets rising main and cable length, and raises the head the pump must overcome - which pushes pump size and cost up together. |
| Required flow and head | A higher duty point needs a larger, multistage pump and a bigger motor. |
| Single or three phase | Three-phase installations use different control gear and protection. |
| Pump quality and origin | Materials, stage construction, motor build and parts availability all vary considerably between brands. |
| Control and protection specification | Basic control box versus a full panel with dry-run, phase and voltage protection or variable speed control. |
| Electrical supply work | Distance to the board, whether a dedicated circuit is needed, trenching and conduit. |
| Retrieval of an existing pump | Removing a stuck or dropped pump is a separate operation and not always straightforward. |
| Sand or sediment conditions | May require a different pump specification, a shroud, or rehabilitation of the borehole first. |
Related Borehole Services
Pump sizing depends heavily on how deep the borehole is and how it was constructed, both of which are decided at drilling stage - Borehole Drilling Cape Town explains what determines those and why the depth is not known until the hole is finished.
Borehole Pump Prices and Installation Costs
Pump cost tracks the duty point - the flow and head the pump has to deliver - not the size of the property. A deeper borehole needs more head, which means a bigger pump and a bigger cable, so depth pushes this figure up on several lines at once.
| Item | Indicative range | What moves it |
|---|---|---|
| 0.37 – 0.75 kW submersible | R4,000 – R9,000 | Suits shallower boreholes and modest garden demand. |
| 1.1 – 1.5 kW submersible | R8,000 – R16,000 | The common domestic band for typical Cape Town depths. |
| 2.2 kW and above | R15,000 – R35,000+ | Deeper boreholes, higher flow, commercial and agricultural duties. |
| Installation labour and materials | R6,000 – R20,000 | Depth, rising main and cable length, headworks and commissioning. |
| Dry-run and motor protection | R1,500 – R6,000 | The cheapest insurance on the system. Fit it even if it was not there before. |
| Complete supply and install | R15,000 – R45,000 | Pump, pipework, cable, controls, protection and commissioning. |
| Pump removal and refit only | R3,500 – R12,000 | Depth and whether lifting equipment is needed over the borehole. |
These are indicative ranges, not a quotation. They are compiled from published South African supplier and contractor pricing to give you a starting point for budgeting. They are not our rate card, and no figure here is a commitment.
Treat them as a broad guide only. Published borehole pricing in South Africa varies enormously - different 2026 guides quote per-metre drilling rates for the same province that differ by a factor of three - because depth, geology, access, specification, distance and fuel costs all move the number. Depth in particular is not known until the hole is finished. Figures generally exclude VAT unless noted, and change over time. Only an itemised written quote against your actual site means anything.
Borehole Pump Installation FAQs
How do I know which borehole pump I need?
Pump selection needs two figures: the sustainable yield of your borehole with its pumping water level, from a yield test, and the total dynamic head the pump must work against - pumping level, vertical lift, friction losses in the pipework and any pressure needed at the outlet.
With those, a pump is chosen from its performance curve so that its efficient operating range covers your actual duty point. Without them, any selection is a guess, and the usual guess is a pump too large for the hole.
What happens if a borehole pump runs dry?
Submersible pumps rely on the water flowing past them for cooling and lubrication. Running dry causes rapid overheating, damage to the seals and bearings, and often a burnt-out motor - sometimes within minutes.
Dry-run protection prevents this by cutting power when the level drops to the intake or when the current signature indicates loss of flow. It is inexpensive relative to a pump and should be fitted on every installation.
How long does a borehole pump last?
There is no fixed lifespan, because it depends far more on how the pump is matched and protected than on the badge. A correctly sized pump, running within its range, protected against dry running and drawing clean water, can run for many years with little attention.
The same pump oversized for the borehole, cycling frequently, or pumping sand will fail much sooner. When a pump fails early, the cause is usually in the system rather than in the pump itself.
Can I replace a borehole pump with the same model that failed?
You can, but it is worth pausing first. If the original pump was oversized for the borehole, fitting an identical one repeats the mistake and you will likely be back in the same position.
Before ordering, establish why the old one failed, check the current water level and yield, and consider whether demand on the property has changed. A pump replacement is the cheapest moment to correct a sizing error, because the pump is already out of the hole.
Why does my pump keep switching on and off?
Short cycling on a pressure system usually traces to the pressure vessel - either the pre-charge pressure is set wrong or the bladder has failed, leaving too little buffer between the cut-in and cut-out points. A leaking non-return valve produces the same symptom by letting pressure bleed back.
The other common cause is a pump that is simply larger than the demand it serves, so it satisfies the pressure switch almost instantly. Cycling is worth fixing promptly, because repeated starts are hard on a motor.
Does the pump go in at the bottom of the borehole?
No - it is set at a calculated depth, not at the base. The pump needs to sit comfortably below the pumping water level under full load, with margin for seasonal variation, but well clear of the sediment that accumulates at the bottom of every borehole.
Sediment is abrasive and will destroy impellers if the pump draws it in. Setting depth also considers the screened interval so that water flows past the motor to cool it.
Can I use an ordinary surface pump instead of a submersible?
Only in shallow situations. A surface pump lifts water by suction, and suction lift is limited by atmospheric pressure to roughly seven or eight metres in practice - often less at altitude or with imperfect pipework.
That rules it out for most boreholes, where the water level sits well below that. Surface pumps are, however, the standard arrangement for wellpoints in shallow sandy areas, and for boosting out of a storage tank.
Do I need an electrician as well as a pump installer?
It depends on where the scope boundary falls. The submersible cable, joints, control gear and protection are pump-specific and normally sit with the pump installer. The supply from your distribution board to the control point is electrical work and may be quoted separately.
Ask which arrangement applies so nothing falls between the two trades. On three-phase installations in particular, the protection specification matters a great deal and should be discussed rather than assumed.
PUMP NOT KEEPING UP?
Get a quote for a correctly sized submersible pump, properly protected.
Get a Pump Installation QuoteGet a Borehole Pump Installation Quote
Tell us the borehole depth, the yield if you know it, and what the pump needs to supply.
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