25 February 2021

Ask the Expert

The concealed toilet cistern, a guide to choosing the right one


The modern fluid lines of the ceramic WC bowl are highlighted by choosing a concealed toilet cistern for bathrooms. What needs to be seen is on view while what doesn’t need to be seen is hidden away neatly. The concealed toilet cistern: the pros and cons, and how it can transform the bathroom.

Over recent decades the trend in bathroom interior design has been towards a sleeker, more habitable room like treatment of the décor. There are good reasons for this approach that have other collateral benefits as well. The concealed toilet cistern forms part of this evolution in sanitaryware. Accommodating the cistern element of the toilet within a wall void or boxed-out shelf looks neat and results in less cleaning and easier bathroom maintenance. Helping to convert the bathroom into a relaxed Spa-like space the concealed toilet cistern has many advantages over the close-coupled toilet. Here below we look at the why, the how and the where of the concealed toilet cistern.

The toilet is an artefact of two parts

The typical home WC or toilet consists of the ceramic bowl which we sit on, the cistern where water is stored and a release mechanism, the flush. The toilet bowl is either hung off the wall or sits on the bathroom floor. The waste connection is generally hidden by the casing of the bowl. The cistern can be attached above the bowl, on full view as with a close coupled toilet or hidden as with the concealed toilet cistern. When it comes to choosing the concealed toilet cistern: pros and cons of each type must be weighted.

The concealed toilet cistern

One of the most notable recent developments in bathrooms, (since the water-saving dual-flush mechanism) the concealed toilet cistern offers distinct advantages for small bathrooms and en-suites. However bigger bathrooms can also benefit from the clean lines and hidden plumbing that allows the wall finish to take centre stage. Having a greater surface of tiles (or plaster) makes for a less cluttered effect and helps frame the WC treating it almost like a sculptural artefact.




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The concealed toilet cistern: The pros

  • First and foremost bathroom cleaning is made much simpler with the concealed toilet cistern. Especially if the bowl is wall hung. There is less plumbing on display and the wall finish is more prominent (depending on the cistern housing). This can be very attractive when the concealed toilet cistern is combined with a beautiful ceramic tile.
  • Nowadays when we are all more aware of ‘lifetime housing’, future-proofing the home with the concealed cistern allows the push mechanism to be placed at a convenient height. The flush plate can be remotely connected to the valve via a metal cable mechanism. For anyone with limited mobility, this is a practical way to make the bathroom more wheelchair friendly.
  • The concealed toilet cistern saves space so can be very practical for use in small bathrooms and en-suites.


The concealed toilet cistern: The cons

  • The concealed toilet cistern toilet is still not as ubiquitous as the close-coupled toilet and is more expensive to buy. The installation requires greater work and so, therefore, represents a greater overall investment.
  • If there is a problem with the cistern it is more difficult to access so makes repairs more difficult depending on where the cistern is housed.
  • If for some reason the water supply is cut off the cistern cannot easily be filled manually. Similarly, the value for the cistern can be harder to access if the cistern needs to be repaired.

Where to position the concealed toilet cistern

The concealed cistern can be accommodated within the bathroom wall partition or inside a built-out shelf or a piece of furniture. The effects are very different for each of these three options. For a new build bathroom, the partition wall can be designed in such a way that the cistern is housed within and the bowl can also be supported off the partition structure. Here the wall-mounted frame can be as slim as 140mm which allows for an insulated model (recommended to help avoid condensation).

Alternatively, for an existing bathroom, the partition behind the back to wall toilet can be boxed out to above cistern height. The cover panel can then be tiled or painted to match or compliment the bathroom wall finish. The top of the resulting shelf can provide useful additional bathroom storage. And lastly, a combined or sit-alone piece of cabinetry can also house the concealed cistern, placed against a wall. A combined unit might incorporate the WHB as well as the toilet bowl, a good option for an en-suite.

FAQs regarding the concealed toilet cistern

The choice of concealed toilet cistern depends on the particular situation, i.e. whether it’s a new build, a refurb, the type of construction etc. However the actual cistern should be WRAS (Water Regulations Advisory Scheme) approved whatever the final choice.

Seldom in theory but in practice provision must be made for access to the concealed toilet cistern. If there is constantly flowing water in the bowl, if the flush is weak or if it takes longer than usual to fill the tank then the cistern needs to be accessed for repair. Remember toilets are manufactured to last, a life span of 50 years is not unusual, so it’s quite possible the cistern or parts of it, will be replaced several times over the toilet’s life span.

If the cistern is not positioned against a shared wall in a plant room, or storage space where it can be accessed then An access panel is recommended for repairs and/or maintenance. The panel can be incorporated into the flush panel which is located close to the cistern so that a hand can pass through. Alternatively include a panel of ceramic tiles on an MDF backing to match the surrounding wall tiles and place over the concealed cistern.

The trick is to make sure everything lines up in terms of the connections and that once complete the toilet bowl hides any plumbing. This way all that is visible is the bowl itself wither hanging or sitting snugly against the bathroom wall. The guiding principle for all cistern types is the same, below we examine installing a concealed toilet cistern within a bathroom furniture installation.

Firstly line up the toilet pan so that is positioned on the centre line of the waste pipe within the bathroom furniture. Then measure the distance off the flooring for the water feed (connecting the flush) and the waste disposal.

Once noted mark the MDF panel of the furniture to allow for a cut-out that will accommodate both. Remove the panel and with the appropriate cutting tools cut the rectangular opening. Then fit the cistern from above using the proprietary clips and screws supplied for the selected model.

Using a flexi-pipe connect the cold water feed to the cistern. Connect the U bend water pipe from the cistern which will protrude past the carcass of the bathroom furniture. Measure the free distance for the pipe to couple with the lip of the water connection bowl and then cut the protruding cistern pipe accordingly making sure to allow for 5mm leeway.

Similarly with the waste connection pipe measure and cut the 100mm diam. waste pipe accordingly and connect to the soil pipe. Tip: use washing up liquid to lubricate the pipes and their housings when connecting. For the flush plate follow the same procedure but use a jigsaw to cut out the opening in the panel. Its position will depend on the cistern model.

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