Most tank installations leak at the fittings rather than the tank, and at the float valve more often than anywhere else.
A tank that never quite fills is usually losing water at the outlet. Detection services at Leak Detection Johannesburg.
Tell us the tank size, whether it is rain-fed or mains-fed, and if there is a pump.
Get a Tank Leak QuoteWhere Installations Fail
- Outlet and inlet fittings - the tank wall flexes as it fills and empties, and rigid connections work loose.
- Float or ball valve - not closing, so a mains-fed tank overflows continuously.
- Pump seals and unions - dripping on the pressure side.
- Tank wall - UV degradation and stress cracking, usually at the base seam.
- Uneven base - the most common root cause. An unsupported tank cracks itself.
Backup Systems
Since Johannesburg's supply interruptions became routine, a great many homes and businesses have put in mains-fed backup tanks. Where the float valve fails on one of those, the tank tops up and overflows around the clock, and the loss appears on the municipal account without anyone noticing a wet garden.
It is one of the most common causes of a large unexplained bill in Gauteng, and the cheapest to rule out: close the tank inlet isolator and read the meter over fifteen minutes with everything else shut.
Water Tank Leak Prices in Johannesburg
| Job | Indicative range | What moves it |
|---|---|---|
| Tank and connection leak inspection | R850 – R2,200 | Call-out plus inspection. |
| Float or ball valve replacement | R450 – R1,400 | The most common fault. |
| Outlet or inlet fitting reseal | R650 – R1,800 | Tank flange and bulkhead fittings. |
| Pump seal or union repair | R850 – R2,800 | Parts and labour. |
| Pressure pump replacement | R3,500 – R12,000 | By flow rate and pressure. |
| Tank wall repair | R950 – R2,800 | Where the tank is worth saving. |
| Tank replacement, 2,500 L installed | R6,500 – R14,000 | Including base and reconnection. |
| Level base preparation | R1,800 – R5,500 | Prevents the next failure. |
These are indicative market ranges, not a quotation. They are compiled from published South African leak detection and plumbing pricing to give you a starting point for budgeting. They are not the rate card of any company on this platform.
A full 2,500 litre tank weighs about two and a half tonnes. Where the base is uneven the tank distorts and cracks, so replacing a tank without correcting the base simply buys another failure.
Related Services
Frequently Asked Questions
Why does my backup tank keep overflowing?
The float valve is not closing. On a mains-fed tank that means continuous water loss straight onto the municipal account, and it is one of the cheapest faults to fix.
Can a cracked plastic tank be repaired?
Small cracks in the upper wall can sometimes be welded. Cracks at the base seam are structural, and given the weight of water involved, replacement is the safer call.
Can I recover the water a tank overflow wasted?
Realistically, no. There is no standing leak rebate in the Gauteng municipalities, and an automatic filling system draws through your own meter.
You can log a query once it is repaired and ask for an adjustment, but a failed float valve is usually treated as a maintenance matter.
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