Borehole Pump Not Working? Common Causes

A borehole pump that suddenly stops delivering water is frustrating, particularly in Johannesburg where municipal supply pressure can be unpredictable and Johannesburg Water’s own figures show non-revenue water losses of 44.8% — a reminder of just how stretched the city’s network already is. Before you call a technician, it helps to understand what the most common causes actually are, so you can describe the problem accurately and avoid paying for a diagnostic visit that could have been resolved at the isolator switch.

Start here: the electrical supply

The majority of pump call-outs in Johannesburg turn out to be electrical rather than mechanical. Work through this sequence first:

• Main isolator or circuit breaker — check the dedicated breaker for the borehole pump in your distribution board. A submersible pump draws a significant start-up current, and a loose connection or a brief voltage dip from Eskom load-shedding can trip it.
• Control box fuses — most systems have a separate control enclosure near the borehole head. The fuses inside are inexpensive and fail more often than people expect.
• Capacitor failure — the run/start capacitor is the single most common component failure on single-phase borehole pumps. When it fails the motor hums but will not start, or trips the breaker immediately. A qualified electrician can test and replace it for a modest call-out fee before you escalate to a pump pull.
• Undervoltage — sustained low voltage during load-shedding recovery periods can damage motor windings over time. A voltage monitor or pump protector relay is a worthwhile addition if you do not already have one.

The pump is running but no water comes out

If the pump is clearly receiving power and the motor is running, the problem shifts to the water side:

Dry borehole or low water table. Johannesburg’s geology means that aquifer levels can drop seasonally or after prolonged periods of high abstraction. If your pump is set at a depth that was adequate when it was installed but the static water level has since dropped, the pump may be drawing air. A professional can measure the current water level and advise whether the pump needs to be lowered or whether resting the borehole for a period will allow recovery.

Blocked pump intake or impellers. Sand, silt, and iron-ochre deposits can clog the intake screen or seize the impellers. This is more common in boreholes that are not used regularly, or where the pump was sized incorrectly from the outset — something covered in more detail in our guide to choosing the right borehole pump size.

Broken or detached rising main. The pipe that carries water from pump to surface is usually polypropylene and is joined in sections. A joint failure, particularly in older installations, means the pump is running but pushing water nowhere useful. This is only detectable by pulling the pump.

Non-return (foot) valve failure. If the system loses prime almost immediately after stopping, a faulty foot valve is the likely culprit. The tank empties back down the borehole overnight, and the pump labours to re-prime each time it starts.

Motor and mechanical wear

Submersible pump motors are designed to run submerged in cool groundwater. When the water level drops and the motor runs dry — even briefly — it can overheat and burn the motor windings within minutes. This is one of the stronger arguments for fitting a dry-run protection device. Motor rewinds are possible but the cost often approaches the price of a new pump, so get a comparative quote before committing.

Bearing wear is a slower process. You may notice reduced flow rates or higher-than-normal current draw before the pump fails completely. Tracking your flow rate periodically is part of a sensible borehole maintenance schedule and can flag declining performance before it becomes an emergency.

If the fault is beyond a simple breaker reset, getting competing quotes from vetted installers can save you a meaningful amount on pump replacement or repair. Compare 3 free quotes — vetted installers, no obligation.

Pressure tank and surface system problems

Not every “pump not working” complaint actually originates at the pump. The surface components deserve a check:

• Waterlogged pressure vessel — if the diaphragm or bladder inside the pressure tank fails, the tank fills entirely with water and the pump short-cycles (switches on and off very rapidly). This dramatically shortens motor life and can look like a pump problem when the real fault is a R2,000–R5,000 pressure vessel replacement (confirm pricing with a quote).
• Pressure switch failure — the switch that tells the pump when to start and stop can corrode or stick. A stuck-off switch means the pump never receives a start signal; a stuck-on switch means it never stops.
• Leaks in the surface pipework — a significant leak after the pump outlet can prevent pressure from building to the cut-out point, leaving the pump running indefinitely.

Water quality changes as a warning sign

A sudden change in water colour, smell, or taste is not always a pump problem, but it can accompany one. Sand in the water often indicates a pump sitting on the borehole floor or a collapsed screen. Discoloured water after a period of non-use is often a biofilm flush and may clear on its own, but persistent changes warrant a water quality test against SANS 241, South Africa’s drinking-water quality standard, before you continue using the water for domestic purposes.

When to call a professional — and what to tell them

Call a pump technician or borehole specialist when:

• The breaker trips immediately on reset (motor short or seized pump)
• The pump hums but won’t start (likely capacitor, but could be seized impellers)
• You suspect the pump needs to be pulled from the borehole
• Flow rate has declined noticeably over several months
• The borehole has not been professionally inspected in more than two years

When you call, have this information ready: the pump make and model (usually on a plate near the control box), the installed depth, the approximate age of the system, and whether there was any unusual event before the failure — a lightning storm, a long power outage, or a period of unusually high water use. That context halves diagnostic time.

For background on what a properly specified system looks like from the start, the borehole drilling overview covers depths, yields, and what to expect from reputable installers. Typical complete borehole systems in Johannesburg run R40,000–R150,000, with most falling between R60,000 and R100,000 — so protecting that investment with a working pump-protection relay and a regular service is straightforward economics.

If a pump pull or full replacement looks likely, comparing installer rates before you commit is worth the ten minutes it takes. Get 3 free borehole quotes — vetted installers, no obligation.

Preventing the next failure

Most borehole pump failures are either electrical (protect with a pump guard relay and surge arrester) or wear-related (catch early with annual flow-rate checks and a two-yearly professional service). Dry-run protection is non-negotiable if your borehole sits in an area with variable water table levels. A pump that costs R15,000–R35,000 installed is worth protecting with a R1,500–R3,000 protection package — confirm exact costs with your installer, as component prices shift with the rand.