TL;DR
- The temperature and pressure safety valve is the part that stops a geyser bursting. When it seizes, the tank becomes the weakest point. It is also one of the cheapest parts on the installation.
- Look at the overflow pipe outside. A stain, a wet patch or a lime streak down the wall is your geyser telling you something, months before anything dramatic happens.
- Scale and pressure are what shorten a geyser's life in this valley. Borehole and hard water bring the first, the mountain slope brings the second.
- Insurance covers a sudden burst and the damage it causes. It generally does not cover a gradual leak, rust, or a tank that was never maintained.
- Phone your insurer before you appoint anyone. Most send their own accredited plumber, and going ahead on your own can cost you the claim.
- Past about ten years, plan the replacement. Choosing the day is much cheaper than the day choosing you.
September is the right month for this. The cold fronts are behind us, the geyser has just come through its hardest three months of the year working the longest hours it will work, and nothing is currently going wrong. That last part is exactly why it is the right time. Every burst geyser we get called to was, the week before, a geyser that seemed completely fine.
A geyser is a sealed steel tank holding a couple of hundred litres of water, usually sitting in a roof space directly above the rooms you care most about. When one lets go, the water damage to ceilings, cornices, cupboards and floors is almost always worse than the cost of the geyser itself. And the frustrating part, the part worth twenty minutes of your time this week, is that most of them give plenty of warning first.
What this valley does to a geyser
Geysers fail everywhere, but they fail faster in some places than others, and Paarl has two of the main accelerants.
The first is scale. Every time hard water is heated, minerals come out of solution and settle on the hot surfaces: the element and the floor of the tank. That layer does two things, both bad. It insulates the element, so the element runs hotter than it was designed to and eventually burns out. And it forms a crust on the tank floor that traps moisture underneath it against the steel, which is where corrosion quietly starts. If your home runs on borehole water this happens considerably faster, and it is one of the things we cover in more detail in our guide to borehole water in Paarl.
The audible symptom is worth knowing: a geyser that rumbles, pops or kettles while it heats is a geyser with a scale problem. That noise is water trapped under the scale layer flashing to steam. It is not dangerous in itself, but it tells you the tank is no longer in the condition it was installed in.
The second is pressure. Paarl is built on a slope, and mains pressure varies a great deal depending on where your house sits relative to the reservoir feeding it. Properties lower down the slope can see genuinely high pressure, and a geyser is rated for a specific working pressure, commonly 400 kPa. The pressure control valve on the cold inlet is the part that keeps mains pressure down to what the tank can take. When that valve fails, the tank is simply exposed to whatever the street is delivering, day and night. We wrote about the underlying cause of all this in why your water pressure changes in Paarl.
Add the two together and you get the local pattern: a tank that has been quietly corroding under a scale layer for years, being held at a pressure it was never meant to see, with a safety valve that has seized shut because of the same scale. That is the recipe.
The one part worth understanding: the T&P valve
If you take one thing from this article, take this.
Your geyser has a temperature and pressure safety valve, usually called the T&P valve. Its whole job is to open and let water out if the pressure or temperature inside the tank climbs past a safe point. It is the last line of defence the system has, and under SANS 10254, the standard that governs fixed electric water heater installations in South Africa, it is required along with vacuum breakers on the hot and cold lines and a drip tray plumbed to discharge outside the building.
Here is the problem. That valve has a seat and a spring, and it sits in hot, mineral-rich water for years without ever being operated. Scale builds up around the seat. Eventually the valve is effectively welded shut. Nothing changes, nothing leaks, nothing looks wrong, and the geyser keeps working perfectly.
Then one day the thermostat sticks on, or the pressure control valve fails, and the pressure inside the tank starts climbing. The valve that should open does not. And because every other part of the installation is stronger than the tank, the tank is what gives.
Why we do not tell you to test it yourself
The standard advice is to lift the lever on the T&P valve once or twice a year to make sure it still moves. That advice is sound in principle, but there is a catch nobody mentions: if the valve is old and scaled, lifting the lever can stop it seating again afterwards, and you go from a valve that was silently seized to one that drips continuously into your ceiling overnight. It also discharges genuinely scalding water. Look at the overflow outside by all means. Leave the lever to someone who has a replacement valve in the van.
The seasonal check, from the ground
None of this needs you in the roof space. Most of it you can do from your garden and your bathroom.
- Find the overflow pipe outside and look at where it lands. This is the single most informative thing you can see. A small amount of water during a heating cycle is normal, because water expands as it heats. A permanent wet patch, a white lime stain, a rusty streak down the wall or moss growing at the discharge point all mean that valve has been passing water regularly, and that is worth a call.
- Check the ceiling under the geyser. You are looking for staining, a faint brown ring, a sag, or a hairline crack in the plaster. Ceilings show a slow leak long before anything drips.
- Listen while it heats. Rumbling, popping or a kettle-like noise means scale. Worth having the element and tank looked at.
- Run the hot tap and feel the temperature. If it is genuinely scalding, the thermostat is set too high. Around 60 degrees is the usual target: hot enough to be safe bacterially, not so hot that you accelerate scale and risk burns.
- Check the pressure at a tap. If your mains pressure feels aggressive, or you have had taps and cistern valves failing more often than seems reasonable, the pressure control valve on the geyser is worth checking at the same time.
- Find the age. There is a plate on the tank with a manufacture date on it. If you cannot get to it safely, your plumber can read it next time they are there. Age changes the whole calculation.
Then there are two things that genuinely need a plumber, and they are the two that matter most: testing the T&P and pressure control valves, and inspecting the sacrificial anode. The anode is a rod inside the tank made of a metal that corrodes in preference to the steel around it. It is a consumable part, deliberately. In hard or borehole water it can be eaten away in a few years, and once it is gone, the tank is next. Almost no geyser in the Winelands has ever had its anode looked at, which is a large part of why tanks fail at ten years instead of twenty.
A reasonable rhythm
Have a look yourself twice a year, going into winter and coming out of it. Have a plumber check the valves and the anode every two years on municipal water, and every year if you are on borehole or notably hard water. That is the whole maintenance programme, and it costs a fraction of one claim excess.
What your insurance will and will not pay for
This is where a lot of Paarl homeowners get an unpleasant surprise, so it is worth being precise. The general shape of South African buildings cover is consistent across insurers, but your own policy schedule is the thing that actually governs it, so read that too.
Usually covered: the sudden and unforeseen bursting of the geyser, the replacement tank, and the resulting water damage to ceilings, walls, built-in cupboards and flooring. This is treated as an insured event on most standard buildings policies.
Usually not covered:
- Gradual leaks. The trigger for cover is the word "sudden". A geyser that has been seeping for months is a maintenance matter, not an event.
- Rust and wear and tear. If the assessor concludes the tank failed because it was old and had never been serviced, that is a declinable claim at many insurers.
- Non-compliant or undocumented work. Replacement geysers must be installed to SANS 10254, and a Certificate of Compliance must be issued by a registered plumber and kept on file. No paper trail can sink an otherwise valid claim, even where the workmanship was fine.
- Very old geysers. Many insurers will not cover a tank much beyond about fifteen years, or will contribute only a portion based on its age.
Phone your insurer first, before you phone a plumber
This is the one that costs people money. Most South African insurers appoint their own accredited plumber for a geyser claim, and if you appoint your own and have the work done before they have authorised it, they may decline to pay for any of it. Stop the water, make the house safe, then phone your insurer. The exception is genuine emergency mitigation: turn the water and the electricity off yourself, immediately, because limiting the damage is your obligation under the policy too.
You will also be asked for your excess, commonly a few thousand rand on a geyser claim, so it is worth knowing your number before you need it rather than finding it out on the day.
Signs a geyser is close to going
Very few geysers fail without warning. These are the ones that tend to precede a burst, roughly in order of how seriously we take them:
- Rusty or brown hot water, particularly if the cold runs clear. That is the inside of your tank arriving at your taps, and it means the anode is long gone.
- Water in the drip tray, or any damp in the ceiling below the geyser.
- A steady drip or constant discharge from the overflow, as opposed to a little during heating.
- Hot water that has quietly got worse: running out sooner than it used to, or not getting as hot. Usually a failing element or a thick scale layer.
- Rumbling or banging during the heating cycle.
- The electrical trip going when the geyser switches on. That can be an element that has failed into the water, and it is one to deal with immediately.
- Age past about ten years, combined with any of the above.
If your geyser does burst, the order is: electricity off at the DB board, water off at the geyser isolator or the main stopcock, then phone. Both of those switches are worth locating and showing everyone in the house on a calm afternoon, because nobody finds them well at eleven at night in the dark with water coming through a ceiling. Our emergency plumber page covers what to do while you wait for someone to arrive.
Replacing on your terms
The genuinely useful thing about knowing your geyser's age is that it converts an emergency into a decision. A tank replaced on a weekday you chose, with the new unit selected on merit and the ceiling dry, is a completely different job from a tank replaced at short notice on a Sunday with a ceiling down and an assessor to satisfy. The first is an appointment. The second is an insurance claim, an excess, and a fortnight of drying and repainting.
So, this month: go and look at that overflow pipe. Check the ceiling. Listen to it heat. If any of it looks off, or if you genuinely do not know how old the thing is, have someone check the valves and the anode while nothing is wrong. We do exactly that as part of geyser repair in Paarl, and when a tank has reached the end, we cover the options, including solar and heat pump, on our geyser installation page.
Twenty minutes now, or a ceiling in August. It is a fairly easy trade.