Toilet Cisterns

FAQs

What is a toilet cistern?

A toilet cistern (often simply called a toilet tank) is the upper reservoir of a toilet system that stores a pre-measured volume of water used to flush the toilet bowl. It acts as a local water accumulator, holding enough water to deliver a rapid, high-pressure release that clears waste into the drainage system. After flushing, it automatically refills and shuts off using internal valves.

What is the difference between a concealed and close-coupled cistern?

The primary difference is visibility and placement: a close-coupled cistern sits directly on the toilet bowl and is fully visible, while a concealed cistern is hidden inside the wall or furniture. 

Here is how they compare across key factors:

Design and Space

• Close-Coupled: The tank and bowl are connected as one visible unit. It takes up more floor space and protrudes further into the room.

• Concealed: The tank is completely hidden. Only the toilet bowl and a flush plate are visible, creating a sleek, minimalist look that makes small bathrooms feel larger. 
  
  

Installation and Cost

• Close-Coupled: Very easy and quick to install. It is the most affordable option and requires no structural wall modifications.

• Concealed: More expensive and complex to install. It requires building a stud wall, using a heavy-duty mounting frame (for wall-hung toilets), or installing a specific toilet furniture unit. 

Are toilet cisterns universal?

No, toilet cisterns are not universal. While they all perform the same basic function, they vary significantly in their dimensions, mounting styles, flush mechanisms, and connections, making them highly specific to the toilet model they are designed to fit.

If you are replacing a cistern, you must match it to your existing setup based on several critical compatibility factors.

What is a dual flush toilet cistern?

A dual-flush toilet cistern is a water-saving toilet tank that features a split-flush mechanism, offering the user two different water volumes depending on the type of waste being cleared. It was invented to significantly reduce household water consumption compared to traditional single-flush models. 

The system uses a divided top button or a specialized lever that connects to an adjustable internal flush valve:
 

• The Partial Flush: Pressing the smaller button releases a lower volume of water. This is designed exclusively for liquid waste. 

• The Full Flush: Pressing the larger button releases the maximum volume of water. This provides the full force needed to clear solid waste and paper. 

How do I know if I need a new toilet cistern?

You generally only need a new ceramic or plastic cistern tank if it is physically broken. However, if the toilet is malfunctioning, you usually only need to replace the internal parts. 

You must replace the entire cistern shell if you notice:

• Hairline Cracks: Even a tiny visible crack in the ceramic or plastic will eventually expand under water pressure and cause catastrophic flooding.

• Leaking From the Tank Body: Water weeping directly through the porcelain material itself (not from a seal or joint).

• Mismatched Bathroom Renovation: If you are buying a new toilet bowl, your old cistern will rarely align with the new bowl's bolt holes. 

Can a concealed cistern be accessed for maintenance?

Yes. Most concealed cisterns include an access point behind the flush plate or furniture panel, allowing maintenance and replacement of internal components when required.

Are toilet cisterns water efficient?

Modern toilet cisterns are highly water-efficient, but older models are incredibly wasteful. The efficiency of a cistern depends entirely on when it was manufactured and the type of internal flush mechanism it uses. Because flushing accounts for roughly one-third of a household's daily water usage, upgrading or managing a cistern is one of the most effective ways to lower utility bills.

What flush button options are available for toilet cisterns?

Flush buttons for toilet cisterns are available in four primary operational categories: top-mounted buttons, wall-mounted flush plates, remote pneumatic buttons, and touchless sensors.

Choosing the right type depends entirely on whether your cistern is standard close-coupled, hidden inside furniture, or concealed behind a wall.