A National Water Deficit
A national water deficit of 5 billion litres per day is expected by 2050 under the current water provision. This translates to the need to increase public water availability by over a third. The expected deficit is driven by climate change and increased demand, but it is also a consequence of multiple historical factors. When canal usage in the UK peaked in the late 18th century, small meandering streams were converted into large, straight watercourses, meaning water now moves more quickly out to sea. Additionally, draining wetlands for agriculture has reduced the soil's capacity to retain water. Another challenge is the difficulty of building new reservoirs, as England is one of the few countries in the world where water is fully owned by private companies that have little incentive to invest in infrastructure.
Climate Change and Regional Pressures
Climate change is having seemingly contradictory effects on UK weather patterns, bringing both record levels of rainfall and severe droughts, such as those experienced in the summers of 2018 and 2022. Increased unreliability in hydrological patterns is likely to place the most stress on South-East England, the region most vulnerable to drought. Over half of this region depends on underground aquifers, which rely on annual winter rainfall.
Parts of Sussex, Cambridgeshire, Suffolk, and Norfolk are already experiencing pressure on water supplies due to demand from new housing developments and businesses. The UK’s water challenges are therefore more about distribution rather than widespread water scarcity. While local water surpluses help reduce the overall national deficit, infrastructure investment is needed to transfer these surpluses efficiently. Without strengthening the resilience of the water system, the National Infrastructure Commission estimates that the daily economic cost of water restrictions (such as the 2022 hosepipe ban) could reach £1.3 billion.
Water Credits as a Short-Term Solution
A water credits system was introduced in Cambridge as a short-term solution to address local water shortages. Water companies are working on improving infrastructure, including new reservoirs and pipelines, to increase water availability while protecting the vital chalk aquifers that supply most of the city and support biodiversity. These aquifers are globally rare, with England hosting 85% of the world’s remaining chalk streams.
The water credits scheme operates by offsetting increased water demand through investment in water-efficient devices in both existing and new buildings. Modelling by DLUHC suggests the scheme could offset enough water loss to ensure a sustainable water supply for the Cambridge area. The system also incentivises developers, as they can earn financial benefits based on their water credits, which are awarded according to water efficiency calculations verified by an accredited professional. This mirrors existing carbon credit and biodiversity net gain standards.
Desalination: A Future Alternative?
Desalination is being explored as a potential method to generate additional water. This process involves removing mineral salts from water, primarily seawater. It is already the primary freshwater source in many arid and semi-arid regions, including several Arab countries.
South West Water is currently constructing a desalination plant in Cornwall with an initial capacity of 2.5–5 million litres per day, with plans to eventually expand production to 20 million litres per day. However, there are several environmental challenges to scaling up desalination nationally, including brine discharge management and greenhouse gas emissions.
Despite these challenges, desalination is becoming more efficient. The water production costs of large-scale, renewable energy-assisted desalination systems remain higher than those using traditional fossil fuels, but technological advancements are improving its feasibility. South West Water has secured a 100% renewable energy supply contract for the proposed plant, and with the UK targeting 100% net-zero electricity by 2035, desalination could become a more environmentally viable option in the future.
Long-Term Solutions for Water Security
South-East England is the driest region in the UK, yet water availability is critical to meeting government aspirations for economic growth in East Anglia. The Cambridge water credits system could serve as a model for how the government can help ease the strain on the national water system.
However, long-term solutions will require large-scale investment in water infrastructure and the exploration of alternative methods such as desalination, especially as it becomes a more sustainable and cost-effective solution.