Regardless of whether you have a combi boiler that provides hot water on-demand or a conventional or system boiler that uses a hot water tank to heat and store hot water for later use, having access to water at the perfect temperature is something that many of us may take for granted. So, when you step into the shower to find that the water is running cold, you might wonder why.

To figure out why you might be experiencing this problem, we’ve taken a look at some of the most common reasons and the steps you can take to rectify the issue. 

A hand checking the temperature of water from a shower

 Why is my shower cold?

If your shower is cold, you should check your boiler or water tank first to ensure they are turned on and programmed correctly. If you carry out these checks and the problem persists, here are three reasons why it might still be happening and what you can do about it. 

You’ve run out of hot water

As obvious as it might seem, you could simply have run out of hot water. Especially in a busy household of a large family, you may find that your hot water supply runs out quickly, meaning that by the time you step into the shower, the water is running cold. The hot water may also run out if you’re using a number of appliances at the same time, such as a dishwasher and washing machine. As a result, you could find that the water coming out of your shower is lukewarm or cold.

Once the hot water has run out, you’ll need to wait for your tank to heat up again. To avoid being caught out, try to avoid showering at the same time as others. If the problem is ongoing, you might benefit from investing in a more powerful water tank to keep up with the demands of your household.

The hot water tank is set too low

You may find that your shower keeps going cold if your hot water tank is simply set too low. Generally speaking, most domestic hot water tanks are usually set at a temperature of around 60 to 65 degrees. This temperature is high enough to kill off harmful bacteria in the water, but it isn’t high enough that the water will come out of your taps too hot and put you at risk of scalding yourself.

However, your water tank might not be set at the optimum temperature for you and your household. The good news is, you should be able to adjust this temperature easily using a dial or a digital interface on the outside of the tank. 

A faulty shower mixer valve

Have you noticed that your water runs hot one minute but then suddenly turns cold? Inconsistent water temperature can be irritating when you’re trying to enjoy a relaxing shower. To help you figure out why this might be happening, check out these three common reasons and what you can do to fix them. 

Why does my shower go hot and cold?

This may seem like an obvious fix, but you should also check that your home has a sufficient water supply. If you don’t have water coming from any taps, whether hot or cold, then there may be a temporary supply interruption. You could contact your provider to see if they can help you out or give you any more information, or you could wait for normal services to resume.

If you have a conventional boiler system, you may wish to check that there is water present in the cold water tank (usually located in the loft). A tank that has run dry could demonstrate problems with the ballcock, which would prevent it from refilling itself as needed. 

Multiple appliances are running at once

Did you know running multiple appliances at the same time can impact the temperature of water coming from your shower? Whether you’ve recently put a laundry load in the washing machine, turned on the dishwasher or someone is using the kitchen sink while you’re taking a shower, you could find that the water struggles to get to and stay at the right temperature as it is being directed elsewhere.

Simply getting into the habit of avoiding running other appliances while you’re using the shower should ensure that the water remains at a consistent temperature.


Limescale is caused by a buildup of mineral deposits in hard water and it has the potential to damage appliances such as kettles, dishwashers and washing machines - as well as boilers and water heaters. As a result, it’s possible for limescale to build up inside an electric shower, or even in the combi boiler itself, and cause a blockage. In turn, this can affect the pressure and cause poor water temperature control, meaning that your shower could be running hot one minute but cold the next.

The good news is, you may be able to solve this problem yourself by using a high quality descaling agent. You can also add a water softener to the mains water supply to prevent a buildup of limescale happening again in the future.

Low water pressure

Low water pressure can be another reason why your shower may run cold. This problem is especially common in multistorey style buildings where a lot of people are relying on the same supply of water at the same time. However, even if you don’t live in a high rise, you could still experience this problem.

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