England's 5-billion-litre water gap will not close by telling people to use less

University of Surrey, Institute for Sustainability

Every day, England falls roughly five billion litres short of the water supply it will need by mid-century. The government's primary tool for closing that gap on the demand side - smart metering - is projected to save about 450 million litres per day by 2050. That leaves a very large hole to fill.

According to the Environment Agency, 60% of the projected deficit must come from reducing demand. And according to a new report led by the University of Surrey, the sector's approach to reducing demand is built on a flawed assumption: that if you tell people how much water they use, they will use less.

135 to 150 litres per person, mostly on autopilot

The average English person uses between 135 and 150 litres of water per day. A substantial portion of that goes to activities that are essentially automatic. People do not consciously decide how long to shower. They do not deliberate over each toilet flush. They do not weigh the merits of reporting a dripping tap versus ignoring it. These are habits - behaviors repeated so often they run on autopilot, resistant to the kind of informational campaigns that dominate water conservation efforts.

The report, titled "Promoting domestic water efficiency via behaviour change," was published to coincide with World Water Day on March 22, 2026. It draws on input from more than 100 professionals across 60 organizations in the UK water sector, gathered between October 2024 and April 2025. Co-authored with researchers from Swansea University, the University of Bristol, and the University of Portsmouth, it maps where the sector thinks behavior change is most needed - and reveals a fundamental disconnect between priorities and practice.

The bathroom dominates the priority list

When water sector professionals were asked to rank the most important behavior change targets, three activities rose to the top: reporting or fixing in-home leaks, showering, and flushing toilets. Four of the six highest-priority behaviors identified were bathroom-based.

The numbers explain why. Showering typically uses between six and 15 litres per minute, depending on the showerhead and water pressure. A 10-minute shower can consume 60 to 150 litres - potentially more than half of a person's entire daily usage in a single activity. Meanwhile, a quarter of all drinking water used in UK homes goes to flushing toilets. These two behaviors alone account for a disproportionate share of domestic water consumption.

But here is where the disconnect appears. The same professionals who ranked showering and toilet flushing as critical behavior change targets placed relatively low value on understanding why people shower the way they do or flush the way they do. The report argues this is exactly backward. You cannot change a behavior you do not understand, and understanding habitual behaviors requires more than asking people to use less water.

Why motivation-based campaigns hit a ceiling

Most water conservation initiatives to date have focused on increasing motivation. They tell people about water scarcity. They show people their usage data. They appeal to environmental responsibility. These approaches can work for deliberate, conscious decisions - like choosing to install a water-efficient washing machine or planting drought-resistant landscaping.

But they are poorly suited to habitual behaviors. Professor Benjamin Gardner, lead author and Director of the Habit Application and Theory group at the University of Surrey, explains the problem in direct terms: people do not consciously decide how long to shower. They simply do it, the same way, every day. Telling them how many litres they are using is unlikely to change that.

Habits persist because they are triggered by context - time of day, location, the sequence of actions that precedes them - rather than by conscious intention. A person can be fully motivated to take shorter showers and still stand under the water for 10 minutes because the behavior is controlled by routine, not by decision-making. Fatigue, distraction, and the simple pleasure of warm water override intentions that were formed in a completely different mental state.

The report points to evidence from the University of Surrey's own research showing that real-time feedback during a shower - delivered at the moment the behavior is happening, not before or after - can meaningfully reduce shower duration. That kind of intervention works precisely because it does not rely on people remembering to act differently. It interrupts the habit loop at the point of execution.

The knowledge-sharing problem behind closed doors

The report identifies a structural barrier that compounds the scientific one. Many UK water companies have conducted relevant behavior change research - pilot programs, customer surveys, intervention trials - but are not sharing their findings with each other. The reason is commercial competition. Companies treat their behavioral insights as proprietary advantages rather than shared resources.

This means the sector keeps re-learning the same lessons, running similar pilots in isolation, and failing to build the cumulative evidence base that would allow more effective interventions. The report argues that standardized behavioral science tools and frameworks could allow companies to share insights about what works and what does not without disclosing commercially sensitive customer data or strategic plans.

Dr. Pablo Pereira-Doel, co-author and Director of the Human Insights Lab at the University of Surrey, frames it as a coordination problem rather than a knowledge problem. The evidence about how to change water-use habits exists in scattered form across the sector. What is missing is the infrastructure to connect it.

Five recommendations, and a note of realism

The report makes five specific recommendations. First, water sector organizations should work directly with behavioral scientists rather than treating behavior change as a communications or marketing function. Second, the sector needs to invest in understanding how people actually use water before designing interventions to change it. Third, water-reduction initiatives should focus on disrupting habits rather than simply educating people about consumption. Fourth, knowledge about effective water-saving strategies should be shared more actively across organizations. Fifth, behavior change should be treated as one approach among several, alongside structural and technological solutions.

That last point deserves emphasis. The report does not argue that behavior change alone can close England's water gap. Infrastructure investment - fixing leaking pipes, building new reservoirs, developing desalination capacity - remains essential. Technological solutions like more efficient fixtures and appliances contribute directly to reduced consumption without requiring anyone to change their habits at all.

Behavior change is one piece of a larger puzzle. But it is a piece the sector has underinvested in, partly because it has relied on the wrong model of how behavior works. Treating water conservation as an information problem - just tell people the facts and they will change - ignores decades of behavioral science showing that habitual behaviors are largely immune to informational interventions.

The gap between knowing and doing

England's water challenge is ultimately a gap between two numbers: how much water the country has and how much it uses. Closing that gap requires action on both sides - supply and demand. On the demand side, the evidence increasingly suggests that the most effective interventions will be those that meet people where they are: in the shower, at the toilet, standing in front of a dripping tap they have been meaning to report for three months.

Not with a brochure. Not with a usage report. With a tool that changes the moment itself.