By Daniel Khamis, plumber and director of All Day Plumbing (licence 339748C).
Quick answer: If your hot water stops working, it doesn’t automatically need replacing. First check the hot water circuit on your switchboard, feel whether the pipes at the unit are warm, and if you have an instant gas heater, look up the error code on the display. Lukewarm water is often the tempering valve, and tripping power is usually a circuit, element or thermostat, which can all be repaired. Rust in your hot water, a popped top or a leaking tank are the clear signs it’s time to replace.
Hot water not working is the most common call we get. Hot water is a real necessity these days, so as soon as it stops, you feel it. Whether you’ve been on the tools or in the office all day, you want a hot shower, so most people want it fixed straight away.
The good news is there are some simple checks you can do at home before you call a plumber.
1. Electric hot water: check the switchboard
If you don’t have gas on in your house, your hot water system is more than likely electric. That’s the tank-looking heater.
Go to your switchboard. There’ll normally be a circuit labelled “hot water” or “off-peak hot water”, something like that.
- If it’s off, turn it on.
- If it trips again, leave it off and call us. It could be the circuit or the heater’s element or thermostat.
- If it’s on, that’s good. Move on to the next check.
2. Check whether the unit is hot
You can normally feel the pipes at the hot water unit. If they’re at least warm, that’s a good sign the unit is heating.
3. Instant (continuous flow) heaters: look up the error code
Instant heaters show an error code on the display. Look it up on Google and it’ll tell you what’s going on, for example no gas, low gas or no power.
4. Gas hot water tank: the pilot light
Gas hot water systems with a tank have a pilot light. A lot of homeowners call us and say, “I want to relight it, can you show me?” We do give homeowners a safe way to relight it over the phone, and only if they’re comfortable doing it. They follow our steps and can relight it themselves.
If you can smell gas, don’t try to relight it. Turn the gas off at the meter and call us.
5. Hot water only lukewarm? It’s often the tempering valve
Lukewarm hot water isn’t a replacement either. A lot of the time it’s the tempering valve. That’s the valve that mixes the 60 degree hot water with cold water to give you safe 50 degree hot water at your taps.
The valve has a lifespan, the same as the tank does, and a lot of the time it goes before the tank. So sometimes just that valve needs replacing, which is good news.
6. Hot water keeps tripping the power
This can usually be repaired. Tripping power could be the circuit, as above, or the thermostat or elements. These are all replaceable, serviceable parts on the hot water heater.
When your hot water system needs replacing
Some clear signs your heater is on the way out:
- Rusty water. If rusty water is coming out of your hot water taps, your heater is on the way out. It might still be hot, but the tank is about to rust through, so you’re normally pretty close to replacing it.
- A popped top. The top of the tank pops and water leaks out from the top.
- A leaking tank. Water coming out of the tank itself, not the pipework.
If you see these signs, it’s worth looking at a replacement before you’re left without hot water.
When to call us urgently
If your tank is inside and it’s leaking all over, it’s urgent. The first thing to do is turn your main water off. If it’s safe to reach, also switch off the hot water circuit at the switchboard, or the gas to the unit. If you don’t know where your main water is, give us a call and we can help you over the phone, and book you in for same day service.
Frequently asked questions
Why is my hot water not working but the power is on?
That’s usually an element. The power is on, but the element needs replacing. That’s a repair, not a new unit.
Why is my hot water only lukewarm?
More than likely the tempering valve, the mixing valve that blends hot and cold water to a safe temperature.
Is a leaking hot water system dangerous?
If it’s inside, it can definitely cause a lot of damage. If it’s outside and draining away safely on the ground, it’s mostly harmless, apart from the water being very hot.
A relief valve that drips a little while the water is heating is normal. A steady stream from it isn’t, so give us a call.
How long should a hot water system last?
The age old question. Ten years seems to be what everyone says, and we agree. We do a lot of replacements at that ten year mark. Some last 12 years, some last 8. Some of the old heaters lasted 20 years plus. Look after it and keep it out of the weather, and it’ll last longer. There’s more in our guide to how long hot water systems last.
Can I reset my hot water system myself?
Not really. A hot water system isn’t a computer, so turning it off and on again more than likely won’t fix it. About the only time a reset helps is with an under-bench Zip or Billi boiling water unit, and that’s not a normal hot water system.
Still no hot water?
Call us on 1300 301 354, 24 hours a day. Monday to Friday, 7am to 5pm (excluding public holidays), our call-out is $0, and that includes a fixed quote. You can also book online and save $50 when you accept the quote (offer conditions).
Need a new system? Get a hot water price online.