In recent months, some UK newspapers have been speculating that dual flush toilets could potentially be withdrawn from the market because there is a concern that they can leak. David Meacock, technical director at Cistermiser, explains that dual flush toilets can save water and perform as intended – but unless leaks are rectified, and consumers are helped to understand the two different flushes, discussions about their possible retraction from the marketplace could continue.
“Over the last two decades, dual flush toilets have become increasingly popular for homes as well as for commercial and public sector washrooms – we’d suggest they represent the majority of the UK toilet market. They were primarily introduced to help reduce water consumption; in theory, each flush should either use four litres of water (if the smaller, part flush is selected) or six litres (if a larger, full flush is required). Before the Water Supply (Water Fittings) Regulations 1999 put stipulations in place to restrict the amount of water flushing devices are allowed to use, the maximum volume of water permitted for toilets was 7.5 litres per flush.
“While dual flush toilets were designed to save water, it is true to say that some can potentially waste water. At Cistermiser, we are keen to help guide our customers to understand and address the issues to ensure that dual flush toilets operate efficiently and are saving water. In turn, this will help balance speculation about such solutions potentially being withdrawn, which is negatively impacting the industry and consumer confidence.
“There are two reasons why dual flush toilets can potentially waste water – the main one being that some types can be prone to leaks. However, the belief that all dual flush toilets leak and therefore need to be removed from sale is a myth that we wish to dispel.
“According to Waterwise, between five and eight per cent of UK toilets are leaking, wasting as much as 400 million litres of clean, fresh water every day. The problem generally lies with the type of valve predominantly used in dual flush toilets – and the issue is completely preventable.
“Traditional single flush toilets operate with a siphon, but in dual flush toilets, drop flush valves are typically used. Studies found that around 80 per cent of leaking toilets had a flush valve mechanism rather than a siphon. Drop valves usually start leaking because the flush seal – which is situated below the cistern’s water line – degrades. The regular operation of the valve opening and closing will be enough to cause degradation. It is very common for water to contain limescale deposits and debris, which over time can degrade the seal. In addition, chemicals in the water can prematurely age seals made from rubber. Flush valve seal degradation is the most common single cause of leakage (it can also be caused by faulty fill valves and faulty dual flush valves).
“It is very difficult to identify a leaking toilet, so the problem often goes undetected for some time. Research suggests that a leak needs to reach around 300 litres of water a day before the issue is recognised (at the point when the leak becomes audible or more visible or water bills become noticeably higher). We therefore strongly recommend that building and facilities managers proactively monitor for leaks on a regular basis. It can be a very worthwhile exercise, as it’s estimated that a third of commercial washrooms have at least one leaky toilet. While leak strips are available, placing some dry toilet paper on the back of the pan will do the same job – if it becomes wet, there is a leak.
“If a leak is found, it’s essential to fix it – every leaking toilet could be wasting between 215 and 400 litres of water on average per day, and costing between £218 and £405 approximately per year (so, if a washroom had six leaking toilets, the yearly cost could be close to £2,500).
“Degraded seals can be replaced – but this is likely to prove false economy. While seals are inexpensive, a plumber will usually be required to install them (which could be costly) and the new seals will probably degrade in the future, resulting in the issue recurring.
“Upgrading the valve to a type that is guaranteed to prevent leaks will be more cost effective and financially astute in the long term. Our EasyflushEVO, for example, is a revolutionary siphonic flushing valve that was engineered to not leak. It can be easily retrofitted or installed in new facilities, in either a dual flush or single flush configuration. Unlike drop valves, there is no flush seal below the water line, so it will not leak due to debris, scale or degradation of the seal. EasyflushEVO also self-cleans to protect against limescale. Each unit can save up to 146,000 litres of water per year and a return on investment can be achieved in just seven months.
“The second reason why dual flush toilets can potentially waste water is related to consumer behaviour. If operated correctly, the use of the smaller/part flush can potentially save approximately two litres of water on every flush. However, research suggests that the different flushes are not fully understood by consumers. A study from WRAS revealed that 80 per cent of people were inadvertently wasting water by choosing the wrong button. Furthermore, users who select the incorrect flush might need to re-flush, using eight or even 10 litres of water in total – far higher than the volumes dual flush toilets are actually supposed to use.
“Simple, clear, user-friendly flush controls (whether push button or non-touch) are a necessity – and this is something we extensively researched in the design of EasyflushEVO. It has a sensor-activated, intuitive user interface to help users differentiate between a part and full flush. Increasing consumer awareness of the different flush functions and their water saving capabilities is also essential – in commercial and public sector washrooms, this could be achieved through prominent, easy-to-understand signage, for example.
“Despite Government plans for reducing water wastage in the UK (such as lowering individual demand from 144 litres a day to 122 litres a day by 2038 and developing minimum product standards for the water efficiency of toilets, showers and taps, including mandatory labelling), we can’t realistically see dual flush toilets being withdrawn from the market. However, addressing and resolving water wastage from dual flush toilets is crucial; it would be a significant step towards changing the rhetoric around them, and, more importantly, would have a hugely positive impact on UK water resources.”
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