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Some of us can’t stop talking about it – frequency, consistency, trends – others prefer to stay tight-lipped. But one thing is generally unquestioned: the yank of the flush, the whirl of the bowl and poof! the poop is gone. This way of life, however, is becoming increasingly untenable. A looming water crisis means we might need to rethink the our whole approach to the toilet.

Each day, you expel about two litres of urine and 150 grammes of faeces on average (even more if you’re dutifully eating your fibre). But to expediently whisk effluent away, the water-based sanitation systems adopted across the world swallow a staggering volume of clean water. In the UK, each flush gulps down an average of nine litres, making the toilet is responsible for about 30 per cent of the total water used in a home.


In light of projections that the UK will run short of water by 2050, this is starting to look a little profligate. “In the next five, ten – and definitely 20 – years, we will start to experience water shortages,” says Stephanie Hurry, head of water efficiency engagement at the water efficiency not-for-profit Waterwise. Increasingly dry weather is a major contributor to water shortages – some areas of South England are becoming so arid that the Environmental Agency has predicted a hosepipe ban next summer. Reckless water usage is also a factor – the average UK citizen splashes 140 litres down the drain every day.

What could alleviate our huge toilet-based water reliance? This week scientists at Penn State University unveiled a spray-on coating designed to make the toilet bowl slippier, and encourage the swift downward passage of any stubborn residue. But while helping to ward off the dreaded two-flush toilet visit, this might not be radical enough.

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“The ultimate environmentally friendly toilet is one that doesn’t use water and doesn’t use electricity,” says Patrick Boylan, founder of Toilet Revolution, purveyor of environmentally-friendly toilets from low-flush to composting models. At the moment, environmental reasons aren’t the main reason people are opting for these. Boylan says 95 per cent of his custom is driven by necessity, and he caters to off-grid locales like national parks, campsites, or churches.

An increasingly desiccated UK could prompt a shift down the composting route. But how do these toilets work? Two main types of composting toilet straddle a great scatalogical divide: whether to mix together or divide urine and the euphemistically termed ‘solids’. “The ones that don't are what I call an internal composting toilet because all the composting happens inside the product, which is kind of what you'd expect,” says Boylan. “The second type is the separating type.” Known as urine diverting toilets, these have two different compartments and everyone – male or female – has to sit down to use them.


Separating the waste is driven by a biochemical imperative. If it remains mixed, the urea in urine degrades into ammonia, which – besides stinking – kills microbes that would contribute to the decomposition of the waste. Diverting urine also means 80 per cent less waste to deal with. However, Boylan says that because the solids on their own are too dry to decompose, they have to be transported to different composting bins or waste processing facilities.

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Clearly, the composting toilet comes up trumps on the eco front, but whether people will willingly make the switch is another issue. How many would opt for handling bags of their own shit over the simplicity of the current system? “You go from flushing and forgetting and paying a small fee that's subsidised, to having to deal with it all yourself,” says Cecilia Lalander, a researcher in environmental engineering at the University of Agricultural Sciences in Uppsala, Sweden. “That's a massive change, and no one will do it. Unless you're a true enthusiast.”

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Less extreme options that can be rigged up in the family home are twists on the traditional water guzzling toilets, like low-flush or dual-flush varieties. We’re most familiar with dual flush – the ones with two buttons and different volumes of water depending on whether it's pee or poo. Low-flush toilets use less water for every flush. For example, the ones that Boylan sells flush using between 300ml and 2.5 litres. Most homes in the UK now have dual flush toilets, but there are other innovations on the horizon.


Air-assisted toilets save water by using air to push the contents out of the bowl. One UK company, Propelair, sells models that it claims use only one litre per flush, compared to the UK average of nine. You use it by shutting the lid, which creates an air-proof seal. Some water enters the pan as well as air which forces the contents down before refilling with a small amount of water. Other air-based systems include pressure assisted, vacuum – the type used on planes – and compressed air toilets. However, these toilets are also louder and more expensive than standard models, meaning they’re not commonplace in homes just yet.

A more mainstream water-scrimping bathroom innovation is waterless urinals. “Each regular urinal uses something like 50,000 litres of water per year,” says Boylan. “There is a big potential water saving on a country-wide basis by simply changing to waterless.” These work with a product called Urilock, a special sealing oil that is poured into the urinal. It’s lighter than urine so creates a barrier that odours cannot escape through, and only requires changing once every three months. Boylan says big corporations choose to switch to these to flex their green credentials. Hotels are another big source of demand. “Hotels use a huge amount of water in terms of washing sheets and towels everyday,” he says. “It’s is a cost matter as well. They get to be environmentally green and to cut costs.”

But it’s not just the flushing itself, leaks in toilet pipes are also a huge source of water waste. Waterwise has found that between five and eight per cent of all toilets in the UK are leaking. “It's a big problem across the industry – we are finding that leaking toilets generally waste between 250 and 400 litres of water every day,” says Hurry.

The biggest culprit is the dual flush. “It tends to be because of the mechanism that is used on the dual flush,” Hurry says. “Sometimes grit can get into it, sometimes it hasn’t been cleaned or maintained over the years. They have a tendency to degrade and unfortunately most people don’t know that” She points out that toilet maintenance is an essential part of the fight against the flow.

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The supremacy of the flushing toilet is a commonly held assumption – with a water-based system generally held up as the pinnacle of progress in sanitation. But some are intent on challenging this. “The water closet is what everyone's trying to strive towards,” says Lalander. “We don't think this is true.”

She believes that a bigger upheaval than alternative toilets is required. “For us, the water bound system is old technology,” she says. “It’s 100 years old; we're just sticking to it.” It’s also true that for many countries in the world, it’s not a realistic option – there’s simply not enough water.

Lalander proposes that using fresh drinking water as a means of transporting poo is highly illogical. In fact, mixing a small amount of waste with litres of high quality water is nonsensical. “It's highly diluted, but it's also polluted,” points Lalander. “What you end up with are large volumes of polluted, diluted water.”

There’s another irrationality tied into the current system. Water from showers and sinks is mixed in with water from the toilet, even though given the former contains chemicals rather than organic waste products, and therefore requires different treatment. The current water treatment system is highly energy and chemical intensive. Operational emissions from the water industry account for nearly one per cent of the UK’s total carbon footprint.

To make their case, Lalander and her research team flip another commonly held perception on its head: that our urine and faeces are even ‘waste’ at all. “If we're looking at it from a nutrient perspective, 80 per cent of the nutrients that we excrete comes out in urine,” she says. Meanwhile, the "faecal fraction" is the only part that contains pathogenic microorganisms. Lalander therefore advocates splitting our waste, and treating this part in separate waste facilities.

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Large volumes of nitrogen in urine could actually make it very useful to farmers. To take advantage of this, Lalander proposes that drying beds be installed in people’s houses, that would process urine into pellets to be transported to farms. This might sound insane to a society that cherishes the swift and immediate dispatch of our business to somewhere far, far away. But in the wake of the climate crisis, we need to get over the intrinsic ick factor and start rethinking our bathroom habits. Tackling the water crisis depends on it.

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