Is your hot water not working?

Generally speaking, your hot water cylinder is a low maintenance appliance, however there are common problems that can keep it from working. When it’s working properly, you usually don’t think about it at all. In most instances, a hot water cylinder that is looked after will last for anywhere between 10 and 15 years. Some even last as long as 20 years, depending on how much hot water you use and how many people live in your household.

From time to time, however, you’ll encounter hot water cylinder problems. Many of these aren’t serious enough to warrant a hot water cylinder replacement. We understand the frustration you feel when your hot water is not working, but depending on what’s going wrong, a simple hot water cylinder repairs may be all you need. 

Our plumbing experts have taken a look at the most common hot water cylinder problems you may come across.

Unusual sounds coming from your hot water cylinder

You shouldn’t hear any strange sounds coming from your hot water cylinder. If you hear any whistling, hissing, banging or knocking around your hot water cylinder, please get in touch with our plumbing experts at Sumich straight away. 

These types of noises are not normal and may indicate a problem with your hot water cylinder or one of its many parts.

When you call us, we’ll ask you what type of noise you hear and when you hear it. Is it always there, or does the sound happen when you turn the water on? Or does the sound come on after you’ve used the water for a few showers? This may indicate that the cause of the noise has to do with the heating of the water, once the cylinder is trying to replenish the hot water.

Water leaking from your hot water cylinder

It’s normal for a small amount of water to come from the hot water cylinder, but a leak or a consistent outpouring of water is not normal, which can cause your hot water to not work.

There are a number of reasons why your hot water cylinder may be leaking – you can read more about these reasons here.

You’re not getting any hot water

If there is no hot water coming out of the shower or the hot water tap, there may be a problem with your water heating system. If you’ve got a hot water cylinder, pay attention to how many showers have been had or how much water has been used. If you initially have hot water, but run out after a few people have had showers, then it may be that you’ve simply used all the hot water in the cylinder and you need to wait for more water to be heated.

If the water runs cold after only one “normal” length shower, or the hot water doesn’t last as long as you think it should, there may be issues with your hot water cylinder. You can check the hot water cylinder thermostat to determine if it’s working correctly. If you have a gas hot water cylinder, there may be an issue with the boiler.

And if you have an electric hot water cylinder, there may be a problem with your power supply. Check whether or not other electrical appliances in the house have shut off as well.

The water is too hot

If all of a sudden the water coming out of your taps is hotter than usual, there may be a problem with your hot water cylinder thermostat. Check that it is set correctly. If it is, the problem may then be with the pressure relief valve – maybe it’s not shutting off properly.

Give us a call right away to have this taken care of. Water that is too hot can be extremely dangerous, causing severe burns, particularly among children or elderly people.

Your water looks or smells bad

Is the water that comes out of your taps discoloured or foul smelling? If so, that could very well be a sign that something is not working properly with your hot water cylinder.

One test that we’ll ask you to do if this is happening is to run the hot and cold water separately. First, turn on the cold water and see whether it is coming out clear and without an unusual smell. If not, there is probably a problem in your pipes somewhere that needs attention. Give our plumbing experts a call and we can help with that.

If the cold water is coming out just fine, next turn on the hot water. If it is coming out smelling bad or is discoloured (yellow or brown), then chances are the problem is stemming from your hot water cylinder and is happening as the water is being heated. Do not use this water. Give us a call and we’ll set a time to come and help. We can also send our emergency plumbing team out if needed.

If you have any questions at all, we’re always more than happy to help. At Sumich Plumbing & Drainage we want all the plumbing and drainage systems in and around your home to work smoothly. But if you ever need us at short notice, we have an emergency team of plumbers available 24/7 – just give us a call on 0800 437 021


There are a number of plumbing and drainage companies in Auckland, so why choose Sumich?

Founded by owner-operator Chris Sumich in 1991, Sumich Plumbing & Drainage has one of the most experienced teams operating in Auckland. Our team has a combined experience of over 100 years and we’ve seen a comprehensive range of scenarios and solutions over the years. Clients trust us to give honest, transparent advice and service.

As registered members of the New Zealand Plumbers, Drainlayers & Gasfitters Association, we are professional, licensed Auckland plumbers for all of your plumbing, drain laying, gas fitting and heating needs. Give us a call to see how we can help.