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Water is a precious natural resource. Not only will saving it mean saving money for your business. It will also reduce associated environmental impacts.

Toilet and urinal flushing can use quite a lot of water. This is especially true for a business with a significant number of toilets. Think of accommodation providers or large visitor attractions.

1. What are water efficient toilets?

Most toilets manufactured since 1991 should be using no more than 6 litres per flush. Some older cisterns can use up to 13 litres per flush though. Check your cisterns to see how much water they use.

A water efficient toilet should be:

  • A full flush toilet of no more than 4.5 litres
  • A single flush toilet of no more than 6 litres

Top installation tips for toilets:

  • Volume adjusters

    To reduce the amount of water used for a flush, you can fit a volume adjuster. You can put the following volume adjuster into the cistern to off-set 1 litre of water per flush or more:

    • Hippos
    • Save-a-flush
    • A filled plastic bottle


    Make sure that you have placed them properly and that they do not interfere with the flush mechanism. Or use a cistern dam to block off a larger proportion of the cistern, again reducing water per flush. We'd recommend this for larger cisterns.

  • Flush mechanisms

    Flush mechanisms like dual flush gives users the choice of two flush volumes. One usually contains 6 litres and the other 4 litres or fewer. Ensure there is clear labelling to avoid confusion and misuse. You can retrofit some dual flush mechanisms relatively easily.

2. Water efficient urinals

Water efficient urinals will help you save on water use. The most efficient of these are waterless urinals. These might need a specialised cleaning regime compared to other water efficient urinals. But they often need less maintenance in general.

  • If you have urinals in your business, it is well worth reviewing the flush controls in place. Urinals are often set to flush regardless of use. This wastes a lot of water – especially out of hours.

  • Uncontrolled urinals will flush around three times per hour, every day of the year. A urinal with a 7.5 litre cistern will be using 197m3 water per year. This will cost you £417 on average in water charges. For larger cisterns this would be even more.

  • You can use or retrofit several devices to control flush frequency. This could reduce you water use by 75%. Waterless toilets can help you save water by 90%.

3. How can I make my toilet more efficient?

You can install sensors or valves to reduce water usage in your washroom. This is how they work:


Passive infrared sensor

  1. 1

    Set up

    The sensor controls a solenoid valve that allows a pre-set amount of water into the cistern per use.

  2. 2

    Regular flush

    When the cistern is full the urinal flushes. This allows you to set it to flush after each use or even a certain number of uses.

  3. 3

    Hygiene flush

    During periods of non-use (i.e. out of hours), you can set the device can to deliver a hygiene flush.

  4. 4


    A passive infrared sensor costs about £120 and is generally easy to retrofit to existing systems.

  5. 5

    Energy use

    Passive infrared sensors either run on a battery (lifetime of 3 to 4 years) or mains electricity.

Hydraulic valve

  1. 1

    Set up

    You can fit a hydraulic valve to the inlet pipework of the urinal system.

  2. 2

    Trigger the system

    When you use water elsewhere, the inlet water pressure decreases. This can happen by flushing the toilet or washing your hands.

  3. 3

    Filling the cistern

    The diaphragm-operated valve opens. This allows a pre-set amount of water to pass to the urinal cistern.

  4. 4


    When the cistern is full, the autosiphon will discharge and flush the urinal.

  5. 5


    When you're not using the washroom, the pressure remains constant so the valve remains closed.

4. Further advice

For more information on water saving opportunities see:

Related links