Pressure-Assisted Toilets | Pros, Cons & Advice

Looking for a toilet that’s got a good strong flush to get the job done? A pressure-assisted toilet could be exactly what you’re looking for to upgrade your flushing power!

In this post, I’ll explain what a pressure-assisted toilet is, how it works and its pros and cons as well as answer some popular questions on the topic.

Let’s dive in!

What Is A Pressure-Assisted Toilet?

A pressure-assisted toilet (sometimes called a power flush toilet) has a pressure vessel inside the toilet tank which uses pressurized air to increase the water flow into the tank and down the waste pipe. Creating a stronger flush.

Pressure-assisted toilets use 3 to 6 litres of water to effectively flush, compared to 6 to 19 litres used in a regular toilet. Making them very water efficient.

They look just like your traditional 2-piece toilet with a cistern on the back. But instead of using simple gravity to work, they increase their flushing power by utilising a pressure vessel and air pressure.

Pressure assisted toilet diagram
Pressure assisted toilet

How does a pressure-assisted toilet work?

A pressure-assisted toilet has a pressure vessel inside the main cistern (toilet tank). As water fills, it also draws air into the pressure tank. Instead of simple gravity drawing water down into the bowl in a regular toilet, the pressurized air pushes the water around the sides of the toilet bowl.

A larger waste at the bottom of the toilet ensures that everything rushes down into the main house drain.

It does not require electricity to create the needed pressure. The motion of water filling the tank sucks air in through a pressure valve and the extra energy is then stored. Most pressure assist toilets have a button on the top of the cistern, instead of a flush lever (although you can get adapters to work with a flush lever).

When you press the button, it opens the bottom of the pressure tank and releases the water.

The flush is considerably louder than a regular toilet. It sounds a bit like a public toilet, but not quite as loud as water pressure in homes is much less compared to office buildings or schools

Children and people with less arm strength may find it difficult to press the button hard enough to get the toilet to flush.

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What is the cost of a pressure-assisted toilet?

The most common brand of pressure assist toilets is the Flushmate, but they are also produced by Kohler, Toto, and other well-known sanitaryware manufacturers. You do spend a little more for a pressure assist toilet with prices ranging from £200 to £400. A traditional toilet costs between £100 and £200.

However, when you consider that you will cut water usage in the bathroom by a third over the life of the toilet, you will earn back the extra cost through lower water bills (If you’re on a water meter).

Installation for a pressure assist toilet is no more complicated than a regular unit. Your plumber will charge the same £100 to £250, and it should take just a couple of hours to switch out the toilet. If you are doing this DIY, put aside a morning or afternoon to tackle the project.

Advantages of a Pressure Assist Toilet

  • Uses Less Water: Some units use just 3.75 litres per flush compared to the 6 litres needed for most modern toilets. An old toilet made before 1995 can use up to 25 litres per flush (that’s 5.5 gallons of water!).

  • Traditional Exterior Toilet Design: A pressure assist toilet blends right in with standard home bathroom design. It’s not bigger, bulkier or look like something out of the future.

  • Keeps the Bowl Cleaner: The added flowrate of water through the bowl created by the air pressure thoroughly scours the side of the bowl with every flush. Compared to today’s 6-litre flush standard toilet, pressure assist will keep it cleaner. And less cleaning is always good!

  • Clogs are Less Likely: The larger waste pipe at the bottom prevents clogs. Even in a busy house, you will be reaching for the plunger much less often.

Disadvantages of a Pressure Assist Toilet

  • More Expensive: You will spend an extra hundred quid or two up front, which can stretch the budget on a DIY bathroom reno.

  • Loud Flushing: If you thought the old flush echoed through the living room, be prepared for a much noisier morning routine as all the kids press the button. Some homeowners actually remove pressure assist tanks due to the noise.

  • Repairs Can Be Pricey: The pressure unit inside your cistern is relatively new to the plumbing world. Not every plumber is familiar with them and the parts are not as easy to source.

  • Pressure Tank Can Fail: The Flushmate toilets have recalled several of their models built between 1996 – 2013. The pressure vessel has been known to fail where the top of the toilet actually flew across the room and the bowl cracked. Only time will tell if the problem has been fixed.

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Can you add pressure assist to a toilet?

No, the bowl and drain of a traditional toilet are not the same shape and size that is needed for premium performance in a pressure-assist toilet. You must replace the entire toilet when upgrading to pressure assist. 

If you see a pressure-assist toilet conversion kit on the shelf in the plumbing department, it is for converting an older pressure-assist toilet into a new and improved system.

Can I convert a pressure-assist toilet to gravity?

Unfortunately, if you take the bowl and waste of a pressure-assist toilet and try to have it use a gravity-flush system, it just does not work. So no, you cannot retrofit a pressure-assist version to a gravity-flush toilet.

However, if you really want to get rid of a pressure-assisted toilet, you can buy a traditional gravity toilet for just £100 to £200.

Are pressure-assisted toilets dangerous?

The Flushmate II 501-B toilet sold between 1996 and 2013 received 1,446 reports in the U.S of bursting. The pressurized air tank developed a leak in bad welds that resulted in the ceramic top blowing off the toilet.

Other models have also been recalled for a variety of parts failures. Some industry experts insist that these failures are due to poor installation, but government safety experts don’t agree.

It isn’t the failed pressure tank that is dangerous. It’s a heavy piece of porcelain weighing 8 to 9 kg. flying across the bathroom that could do some serious harm.

However, Flushmate is not the only brand on the market and the other manufacturers have not seen as many failures since they first hit the market in 1985. Pressure-assisted toilets are seen as a safe and economical alternative by the industry.

Final Thoughts…

There you have it! Everything you need to know about pressure-assisted toilets.

If you’re ever worried about your standard gravity toilet not having enough oomf to get the job done then a pressure assistant toilet will have a superior and stronger flush while using less water.

However, with great power comes increased cost, noise and more parts that could fail on you.


Michael R

Michael is a KBB designer from the UK. He's been designing and project managing new Kitchen, Bedroom and Bathroom installations for over eight years now, and before that, he was an electrician and part of a KBB fitting team. He created The Bathroom Blueprint in early 2020.