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A burst geyser rarely comes out of nowhere. Most geysers give warning signs for weeks or months before they fail. Spot those signs early and you can replace the geyser on your own schedule, instead of mopping water off the ceiling at 2 am.
Warning signs your geyser is failing
1. Water dripping from the overflow pipe
The overflow pipe outside carries water from the pressure valve or drip tray. A few drops while the geyser heats can be normal. A constant drip or steady flow means a valve is failing or the tank is leaking into the drip tray.
2. Damp patches or stains on the ceiling
A brown stain or bubbling paint below the geyser means water is escaping. It may be a slow leak from a joint, or the tank itself.
3. Rusty or discoloured hot water
If only the hot water comes out brown or rusty, the inside of the tank may be corroding. Once the lining rusts through, the tank will leak.
4. Banging, popping or rumbling
Scale on the bottom of the tank traps water, which boils and pops as the geyser heats. In Johannesburg’s hard water, this is common. It means the geyser is working harder and the element is under strain.
5. Earth leakage tripping when the geyser heats
A failing element often trips the earth leakage. It’s not always a sign of a burst, but it often comes with an old, scaled-up geyser.
6. Not enough hot water
If your hot water runs out sooner than it used to, scale may have built up or the element may be failing.
7. Age
Most electric geysers in Johannesburg last somewhere around 10 years, sometimes less in hard-water areas without servicing. If yours is older and showing any of the signs above, plan a replacement.
What causes a geyser to burst
- Corrosion of the tank once the sacrificial anode has worn away
- Hard-water scale that traps heat and speeds up corrosion
- A faulty thermostat that lets the water overheat
- A failed pressure or safety valve that lets pressure build up
- Pressure surges when the municipal supply returns after an outage
What to do in the first 10 minutes
- Switch off the geyser at the DB board. It’s usually labelled “geyser”.
- Close the cold-water supply to the geyser. The isolating valve is usually on the cold pipe next to the geyser. If you can’t get into the roof safely, close the main water valve at the meter.
- Open a hot tap in the bathroom or kitchen to release pressure.
- Switch off lights and plugs in rooms where water is coming through the ceiling.
- Move furniture and electronics, and put buckets and towels down.
- Take photos of the damage for your insurer.
- Call your insurer, then a plumber.
Never go into the roof if water is near the electrical wiring and the power is still on.
Is it a burst, or just a leaking valve?
| What you see | Likely cause |
|---|---|
| Steady drip from the overflow outside | Pressure or T&P valve |
| Water pooling in the drip tray, overflow running | Tank leak or valve |
| Water pouring through the ceiling | Burst tank, or a drip tray that’s missing or blocked |
| Leak at a pipe joint next to the geyser | Joint or fitting, usually repairable |
A valve or joint can usually be repaired. A leaking tank means replacement.
Making your next geyser last longer
- Service it every few years. Replacing the sacrificial anode and descaling the element can add years to its life.
- Set the thermostat to 55 to 60 °C. Higher temperatures speed up scale and corrosion.
- Make sure there’s a drip tray with an overflow to the outside, so a future leak goes outside rather than through your ceiling.
- Replace dripping valves promptly.
What a replacement costs
See our full guide: Geyser replacement cost in Johannesburg.
Geyser burst? Call us
Supa Nova’s plumbers handle burst geysers across Johannesburg. We do the plumbing and electrical connection in one visit, and supply the compliance certificate. See emergency plumber or geyser replacement, or call 082 891 1577.