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Why is My Boiling Water Tap Spitting?

Why is My Boiling Water Tap Spitting?

Are you using a boiling water tap in your home or workplace, only to encounter moments of spitting and popping sounds from the machine? Have you been wondering why this is happening? If so, it may be time to take a closer look at what causes these problems — thankfully, they are often easy to fix.

In this blog post, we’ll go over some common reasons why your boiling water tap might be making those strange noises — and how you can quickly address them.

What Causes a Boiling Water Tap to Spit?

The Boiler Tank Temperature is Too High

One of the most common reasons for a spitting boiling water tap is because the boiler tank temperature has been set too high. We recommend releasing some of the boiling water into your sink, lowering your boiler tank temperature by a few degrees and then testing your boiling water tap again. If the tap still spits after lowering the temperature, test your connections to ensure they aren’t loose – we recommend switching your boiler tank off at the wall while you do this.

Pressure Issues

The most common cause of spitting from boiling water taps is too much water pressure. We generally recommend:

  • Minimum Supply Pressure 0.1 MPa (1 bar)
  • Maximum Supply Pressure 0.5 MPa* (5 bar)

If your pressure is outside of these parameters, we would recommend you get in touch with your plumber. If the tap was fine at the time of installation, a change of pressure may have happened if you have recently changed your plumbing system or added new features like dishwashers. It could also be caused by a faulty part inside the tap itself—for instance, if a hole in one of the pipes allows air into it – so it’s worth checking the individual connections and components of your tap and tank.

Scale Buildup

Finally, scale buildup could be contributing to spitting or spluttering from your boiling water tap. Scale buildup occurs when mineral deposits stick onto surfaces inside your plumbing system over time; these deposits can block valves and impede the normal flow of liquid, leading to pressure imbalances in your boiling water taps and ultimately causing them to spit hot water outwards.

Although our taps come with a filter designed to remove minerals and chemicals – which we recommend you change every 6 months – hard water could cause limescale to build up over time. Follow our guide to removing limescale for advice on dealing with hard water deposits.

Should I Contact a Plumber or Do It Myself?

If you want to act against this problem but are uncomfortable making any changes to your plumbing system, it’s best to contact a plumber or technician for help. They can troubleshoot the issue and make sure that all parts are functioning properly — and if necessary, they can also carry out repairs or replacements as needed. This can help save you money in the long run and ensure that your boiling water tap continues to supply hot water safely and reliably.

Precautionary Steps to Prevent Future Issues

It is important to learn how the tap works and follow the recommended preventive maintenance instructions to prevent future boiling water tap issues. This includes regularly flushing your tap, replacing the filters and checking that the wiring and connection are tight—all of which will help extend the life of your system.

Additionally, following safety protocols such as turning off and unplugging electrical appliances before performing any maintenance will help ensure risk-free repairs. Finally, a certified technician should make any repairs or upgrades if you need further assistance with maintaining your boiling water tap. By taking these precautionary steps now, you can help ensure against future issues for years to come.

Does the Boiler Tank Need Restarting or Flushing Out?

If your boiling water tap has been spitting for an extended time, the boiler tank may need to be restarted or flushed out. This simple maintenance procedure can help restore normal functioning by removing any accumulated rust and dirt particles blocking the hot water flow. Additionally, checking if there is a problem with the cold water feed or pressure of the boiler tank can help resolve the issue.


A spitting boiling water tap can be disconcerting and disruptive, but there are simple steps you can take to try to minimise or stop the problem. By following these tips, you can help keep your boiling water tap running smoothly — and minimise spitting incidents in the future.

Read more about boiling water taps, learn how a boiling water tap works or shop our full collection of boiling water taps.

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