Portsmouth residents urged to help close England's 5 billion litre water gap

University of Portsmouth researchers are calling for a fundamental rethink of how England approaches water conservation, ahead of World Water Day (22 March).

A new report released this week (19 March) has revealed that changing how people shower, report leaks and flush toilets could help close England’s projected five billion litre daily water shortfall - but only if the water sector builds the evidence base to make it work.

The report, Promoting domestic water efficiency via behaviour change, was led by the University of Surrey and co-authored with researchers from Swansea University, the University of Bristol and the University of Portsmouth, including Dr Julia Brown from the School of the Environment and Life Sciences. 

It draws on input from more than 100 professionals across 60 organisations in the UK water sector, gathered between October 2024 and April 2025.

They argue that England's projected five billion litre daily water shortfall cannot be closed by awareness campaigns alone. Most water-use behaviours are habitual and automatic, meaning people do not consciously decide to use more water than necessary. Effective change requires understanding why people behave as they do before attempting to change it.

Portsmouth’s water habits

The findings are particularly relevant in Portsmouth, which has the highest consumption rate in the UK. Portsmouth Water supplies more than 324,000 homes and businesses in the city and surrounding area, and its customers use around 160 litres of water per person per day - well above the national average of around 142 litres. The water company has set an ambitious target of reducing that figure to 119 litres per day by 2050.

Dr Brown, who has been working in partnership with Portsmouth Water for several years, said: “The UK is often viewed as a water-rich country, but the reality is that climate change is seeing a decline in water security, particularly in southern and eastern England where Portsmouth Water operates. There is also a growing concern over the increasing amount of water we take from the environment to meet growing demand - our abstraction of water is beginning to affect some of the rarest habitats in the world.”

Bob Taylor, Chief Executive Officer for Portsmouth Water, added: "We’re seeing increasing pressure on water supplies across the South East, driven by climate change and a growing population. At the same time, it’s vital we protect the environment and make sure there’s enough water left to support nature.

"Our customers rightly expect us to play our part which is why over the next five years, we’ll be delivering our largest ever investment programme. We’re using new and innovative approaches, from satellite technology to specially trained leakage detection dogs, to find and fix leaks more quickly. We’re also rolling out smart water meters and other initiatives to help households find and fix leaks early and have a better understanding of their water usage to support everyone to be more efficient."

Meanwhile, University of Portsmouth PhD researcher Touriya Ghadbar is currently conducting a study in collaboration with Portsmouth Water, looking at how households across the city use water and how better communication can help support water-saving behaviour.

The study is now seeking participants. Anyone aged 18 or over who lives within the Portsmouth Water supply area is invited to complete a short online survey, which takes approximately five minutes.

Touriya Ghadbar said: "What makes this project deeply personal for me is my lifelong connection to the issue of water scarcity. From my early childhood, I witnessed the daily challenges of living without reliable access to water. This experience continues to shape my perspective and drive my commitment to making a meaningful difference, particularly in addressing water use and supporting more sustainable and equitable water practices in the face of growing environmental pressures."

The survey is entirely confidential, and participation is voluntary. Respondents who choose to provide their contact details may be invited to take part in follow-up interviews or focus groups.

"We know that even small changes can make a real difference, and we want to make it as easy as possible for our customers to save water," added Bob Taylor, Chief Executive Officer for Portsmouth Water. "We really welcome this study and our partnership with the University of Portsmouth, which will help us go even further to support everyone to use less water."

The national picture

Nationally, England currently uses an estimated 135 to 150 litres of water per person each day. Smart metering - the main tool in the government’s demand-reduction strategy - is projected to save around 450 million litres by 2050. According to the Environment Agency’s national framework, 60 per cent of the projected deficit must be recovered through demand management, and researchers believe that means changing behaviour at home. 

The national report makes five key recommendations for the water sector: to work directly with behavioural scientists; to invest in understanding how people use water before designing interventions; to focus on disrupting habits rather than simply informing people; to share knowledge more actively across organisations; and to treat behaviour change as one approach among several, alongside structural and technological solutions.

Professor Benjamin Gardner, lead author of the report and Director of the Habit Application and Theory group at the University of Surrey, said: “The water sector knows that behaviour change matters, but it needs to do more to connect with what we know around how people use water. Most initiatives so far have focused on increasing motivation to save water. That approach has its limits - particularly when the behaviours in question are habitual. People do not consciously decide how long to shower, for example. They simply do it, the same way, every day. Telling people how many litres of water they are using is unlikely to change that.”