Double-flushed water-saving toilets are accused of actually wasting more water than savings.

Many of the water wasted in British toilets every day is due to a device designed to prevent environmental problems. According to the BBC, dual flush toilets with two flow options actually waste more water than they save because design problems cause them to leak, and most people don’t know the combination of flush buttons, and surveys found that half of users use them incorrectly.

Double-flushed water-saving toilets are accused of actually wasting more water than savings.

The water-saving toilet is designed to provide a choice of small or large flushes (usually four or six litres) to save water according to the user’s needs. However, waterwise, a water-saving organisation, estimates that 5 to 8 per cent of toilets lose water to leaks – and most of these toilets use this design.

Andrew Tucker, water efficiency manager at Thames Water, said the problem was getting worse as more people were renovating their bathrooms. “As more and more people renovate and retrofit old toilets, and we build more houses, the amount of water lost is getting bigger every day, so we’re actually adding a problem.” He said. The problem is related to the drop valve system used in most double flush toilets, which was introduced in 2001 after a change in UK regulations.

The Association of Bathroom Facility Manufacturers (BMA) says the drop valve system tends to leak more than traditional siphons because debris can easily get stuck in the valve, causing it to keep running.

Jason Parker, managing director of Thomas Dudley Ltd, one of the UK’s biggest water pipe manufacturers, also believes that traditional toilet designs are greener: “The siphon valve doesn’t leak, and the water-saving toilet does?” If we look at the data we’ve got, it could leak within a week of installation, maybe two years, but they’ll end up leaking. “

Rising water demand is a pressing environmental problem, with the head of the Environment Agency warning last year that England will not have enough water to meet demand within 25 years.

Parker wants to reverse that trend, saying, “If we take water waste seriously and really want to stop it, the only way is to put the siphon back.”

Another way in which double flush toilets are generally wasted is because of design inconseication that leads to human error, with a recent study by Thames Water showing that up to 50 per cent of customers use the wrong button or press two buttons at the same time.