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How to fix low hot water pressure

Low water pressure problem in shower head

With winter right around the corner, hot showers will be saving lives – or at the very least keeping you warm as you start or wind down your day. So, the last thing you want is to find that your hot water pressure is little more than a trickle when you step into the shower after a hard day in the cold. 

Now is the time to make sure everything is in working order. If you find your hot water pressure is less than stellar, here are some things that might be causing the problem and what you can do to fix it. 

Debris build-ups

Is it just your hot water tap suffering from low pressure? If so, it may be caused by build-ups in your hot water unit. When sediment and scale accumulate from corrosion and age, it can result in blockages over time that cause low hot water pressure. This can also be caused by minerals in hard water (calcium, magnesium, potassium and sodium). When there is an excess of minerals, it can create a coating inside your plumbing line that results in low pressure. 

What do you do to fix it?  

To confirm whether there is excess sediment or build-ups in your system, fill a container with water from a tap that supplies hot water. Leave it for a while, and any sediment will settle at the bottom. If you find there is a lot, turn on all the taps in your house at once for about two minutes each. This will help flush out your lines and get rid of build-ups. If this doesn’t work, call in a professional to clean and flush your hot water unit. They can also assess what to do if minerals have built up. 

Showerhead issues 

Low water pressure in the shower could be a simple problem that’s easy to resolve. If your low hot water pressure is isolated to this one place, your showerhead is likely the cause. Just like with your pipeline, blockages can accumulate within the showerhead and prevent the flow of water. It may also be from a worn-out tap that needs an upgrade. 

What do you do to fix it?  

Luckily, this is an easy one. For a worn-out tap or showerhead, you can replace this yourself or call in someone to do it for you. For a DIY option, ensure you get the right-sized fixture from your local hardware store. 

If the issue is from a build-up, remove the showerhead and place it in a cleaning solution. There are chemical options out there, or you can simply create a mixture of equal parts water and vinegar. Lemon juice works too. Leave it submerged for 4-6 hours, rinse it, and put it back in place. You should then let it run for about 30 minutes to get rid of any extra sediment. 


Airlocks occur when air becomes trapped in your hot water cylinder, hot pipelines, or header tank. Vapours can get caught in the highpoint of the pipework since the water in the system is denser than the gas produced. This creates a bubble of air that stops water from circulating and flowing as smoothly. If your water is sputtering out of the tap or stopping completely, even though the cold water is function fine, this is a sign you have an airlock problem.  

What do you do to fix it?  

Pipe airlocks are very difficult to clear on your own, but not impossible. You can use a small length of hose and connect it to the hot water tap causing the problem, before joining another hot and cold water tap together with the hose. Create a good seal with a clip or tap to prevent pressure from escaping. Run the working taps for a few minutes, and water should fill up inside the hose, building enough pressure to break the airlock. You should only do this if you feel confident in what you are doing. Otherwise, it’s best to call in a licensed plumber for assistance. 

Damaged pressure valve   

Pressure valves are designed to control your water pressure, allowing water to flow at a consistent rate regardless of the main supply pipe pressure. So, when they get damaged, it can affect the water pressure input and cause spikes and dips in the output. To find out if this is your problem, you will need to get a pressure reading from a portable pressure gauge. 

What do you do to fix it?  

If damaged or broken, you will need to replace your fault pressure valve. You may be able to DIY this but make sure it is the right part for your unit. Otherwise, call in a plumber to get it resolved. 

Mason bees 

At certain times of the year, it’s common for mason bees to enter your hot water system through a vent above your roofline. When you turn your mixer on these annoying creepy crawlies can build up in the valve lifter, limiting and sometimes completely halting the flow of hot water. 

What do you do to fix it?  

This isn’t an issue you can fix on your own. A plumber will need to remove the mixer and disassemble the cartridge or valve lifter, before flushing the legs and bodies out. To prevent this from happening again in the future it helps to fit a gauze mesh at the top of your vent. 

Hot water system issues   

Whether it be old, faulty, or poorly installed, sometimes your hot water system is the problem. It can deteriorate over time and start to deliver water at low pressures, or it can start to leak at pipe joints. Other times, minor maintenance issues might be the issue, or the system was incorrectly installed from the outset. Most commonly, this is caused by mismatched pipe diameters or too many pipe bends. 

What do you do to fix it?  

All roads lead to calling in a professional. If you notice your hot water cylinder leaking, you should contact them immediately to avoid water damage or worse. They may direct you to replace your system, which will get things back in working order. They can also address any maintenance requirements and get things flowing smoothly, or help correct an improper job. 

Contact Allen Plumbing to correct your hot water pressure 

Allen Plumbing & Gas has the experience and knowledge needed to get your hot water pressure flowing at full strength. Whether it be pipe blockages and build-ups, broken assets, replacing or maintaining your hot water system, or anything in between, you can trust us to get the job done. Don’t hesitate to reach out and get your hot water system ready for winter.