• Water guide

The environmental impact of the water industry

The British water industry provides a vital supply of treated drinking water to 50 million homes and businesses and collects and processes 15 billion litres of sewage each day.

Unfortunately, this comes at a high environmental cost. Water companies are responsible for 6% of the UK’s greenhouse gas emissions and are polluting rivers across the country.

This guide explores the environmental impact of the British water industry, why these issues are becoming more urgent, and what can be done to reduce them.

How the water industry affects the environment

The water industry impacts the environment at every stage of the water supply and wastewater cycle.

Here we summarise the five key processes used by British water companies, explaining how they impact the environment.

1. Abstraction from rivers, lakes and aquifers

Public water supply begins with the removal of water from natural sources. High levels of water abstraction reduce river flows, damage habitats and place stress on aquifers that are slow to recharge. In dry periods, this can limit how much water remains available for wildlife and for other users, including agriculture.

2. Treatment and distribution of drinking water

Treating abstracted water so that it is safe to drink requires energy, chemicals and extensive infrastructure. Pumps, filtration systems and disinfection all contribute to the water industry’s carbon footprint. Once treated, water is pushed through thousands of kilometres of pipework, further increasing energy use.

3. Wastewater collection through sewers and storm overflows

Every litre of water put into the drains by businesses or households eventually enters the sewer network. Ageing sewers suffer from leakage, and storm overflows frequently release untreated wastewater, which pollutes rivers and coastal waters, adding nutrients and chemicals that harm these ecosystems.

4. Treatment and discharge back into the environment

Wastewater treatment removes solids, organic matter and contaminants before the cleaned water is returned to rivers or the sea. This process is energy-intensive requiring 0.5 to 2 kWh if electricity per cubic metre of wastewater treated, and can still leave trace pollutants in the environment, including nutrients and microplastics.

5. Sludge and biosolids handling

When wastewater is treated, the solid materials removed from sewage form a by-product called sludge. This sludge contains organic matter, nutrients and trace contaminants. It must be further processed into biosolids before it can be reused or safely disposed of.

Most of the sludge produced by water companies is used on farmland to improve soil, but if it’s not treated or applied properly, it can release greenhouse gases, contribute to nutrient runoff and introduce chemical pollutants into the environment.

Water abstraction, river health and pressure on ecosystems

Water abstraction removes water from rivers, lakes and aquifers to supply homes and businesses. When too much is taken, the natural balance of these systems is disrupted.

Abstraction reduces the amount of water left in rivers and groundwater. Lower flows mean habitats become smaller, temperatures rise more easily, and pollutants become more concentrated. Species that rely on cool, fast-moving and oxygen-rich water struggle to survive when levels drop.

This pressure is most visible in chalk streams. The UK has more than 220 chalk streams, around 85% of the global total. They rely on steady groundwater flow to maintain their clear water, stable temperature and unique ecology. However, only about 17% currently meet “good ecological status,” and many are in decline because abstraction and drought reduce the natural spring flow that sustains them.

Water companies hold abstraction licences that allow them to take water from rivers, lakes or groundwater. These licences set limits to help ensure enough water remains in the environment to support wildlife and natural flows. However, even with these controls in place, demand can still exceed what rivers and aquifers can sustainably provide, especially during dry weather.

Sewage pollution, storm overflows and impact on water quality

The wastewater system plays a major role in the environmental impact of the water industry. Most towns and cities still rely on ageing combined sewers and treatment works that were not designed for today’s population, climate pressures or modern chemicals, directly causing the following environmental consequences.

Combined sewers and why storm overflows happen

Much of the UK still relies on combined sewers, where rainwater and wastewater share the same network of pipes. During heavy rain, sewage treatment works and sewers can become inundated because the system was not designed for the volumes created by growing towns and cities.

When the sewage treatment works reach maximum capacity, water regulations allow a mixture of rainwater and untreated or partly treated sewage to be discharged directly into rivers and coastal waters to prevent flooding.

Sewage discharges and pollution incidents

High levels of storm overflow activity and treatment-plant failures affect inland and coastal environments. According to Environment Agency reporting, serious pollution incidents linked to wastewater systems have risen sharply, with 75 category 1 and 2 cases recorded in 2024 compared with 47 in 2023.

In total, 2,801 pollution incidents were recorded in 2024, many of which impacted rivers, estuaries and the coastal zone. These events degrade water quality, damage marine habitats, and affect shellfish and coastal bathing areas.

Chemical pollution, nutrients and emerging contaminants

Modern chemicals found in household products, medicines and industrial wastewater can bypass sewage works and directly enter both rivers and the sea during storm overflows. Substances such as PFAS, pharmaceuticals and microplastics persist in the environment and accumulate in marine sediments.

Nutrients like nitrogen and phosphorus fuel algal blooms in rivers and coastal waters, which lower oxygen levels and harm fish and invertebrates. Low river flows make these pollutants more concentrated, increasing their impact as they move towards estuaries and the coast.

Sludge, biosolids and waste from treatment

As wastewater is treated, the solid material separated from it becomes sludge. After further treatment, this becomes biosolids, which are often used on farmland or sent for energy recovery.

Energy recovery from sewage directly produces carbon dioxide emissions, but also produces electricity that can be used by the sewage treatment works.

Alternatively, the biosolids are used as an agricultural fertiliser. Unfortunately, the use of such fertilisers causes a further problem during heavy rainfall when the fertiliser directly flows into and pollutes nearby rivers.

Governance and regulatory failure of the water industry

Environmental performance data from recent years shows that water companies in England are not meeting the standards required to protect rivers, coasts and ecosystems.

Pollution incidents are rising, and overall ratings for the sector have fallen to the lowest level since assessments began. These results reveal long-term weaknesses in water infrastructure investment, compliance and regulatory oversight.

Key environmental performance statistics for England:

Source: 2022, 2023, 2024 UK Gov – Environmental performance reports

Why performance is getting worse

Much of the water and sewer network in England is ageing and was built for smaller populations and different weather patterns than we see today. Many assets have not been upgraded fast enough to cope with heavier rainfall or increased demand, which means treatment works and sewers are more easily overwhelmed.

A major reason for this underinvestment is how household and business water rates have been regulated. Ofwat, the industry regulator, has historically kept bill increases very low, limiting the money water companies could invest in essential upgrades and maintenance. Leakage targets have been repeatedly missed, and storm overflow improvement plans are behind schedule.

When treatment works, and sewers reach their limits, untreated or partially treated wastewater is released into rivers, estuaries and coastal waters. As these incidents become more common, the damage to wildlife, habitats and bathing water quality continues to grow.

Green bonds and the concern over greenwashing

Many water companies now raise money through green bonds. These funds are promoted as supporting environmental improvements, including upgrades to wastewater infrastructure and projects to reduce emissions. In principle, this should help improve environmental performance.

However, the ongoing decline in results raises concerns that the benefits promised when issuing these bonds are not materialising. When pollution incidents rise while companies promote green investment, confidence in these claims is weakened and accusations of greenwashing increase.

There is growing pressure on companies to demonstrate that money labelled for environmental improvement is genuinely delivering cleaner rivers and coasts.

Why stronger governance matters

Failing governance and poor delivery have real consequences. Pollution harms wildlife, damages habitats and affects bathing water quality in coastal communities.

Public trust in the water industry suffers when domestic and business water rates increase, but environmental outcomes worsen. Effective oversight, investment and transparency are essential to restore confidence and to ensure improvements are delivered where they are needed most.

How the water industry contributes to climate change and water scarcity

Treating and transporting water requires a constant supply of energy. The more water the industry uses, the more it must pump and process, which increases emissions and contributes to climate change.

Water demand also affects the availability of water in the natural environment. When large volumes are taken from rivers, lakes or groundwater, less water remains to sustain wildlife and natural flows, altering parts of the water cycle that keep ecosystems functioning.

Drought risk in England

Large parts of eastern and southern England are already classed as seriously water-stressed, particularly East Anglia. The region receives some of the lowest rainfall in the country and has high demand from agriculture and a growing population. Most of its public supply comes from groundwater, which can take months or even years to recover after dry weather.

Chalk streams in these areas are among the first to show signs of stress. When water levels fall, flows slow, water temperatures rise, and wildlife declines. During prolonged dry spells, restrictions on non-essential use are often needed to protect remaining supplies and the environment.

Why using less water helps

Reducing water use lowers the amount of energy needed for clean water supply and wastewater treatment, which helps cut emissions. It also leaves more water available in rivers and aquifers during dry periods, improving resilience to drought.

Simple actions such as quickly fixing a commercial water leak or reducing water consumption can reduce pressure on the water system, support local environments and often lower bills at the same time.

What are the general impacts of water industry pollution

When sewage and wastewater enter rivers or the sea, the consequences are not only environmental. Poor water quality also affects people, local economies and community wellbeing.

Public health risks

Polluted water can carry harmful bacteria and viruses. This can cause stomach upset and infections among people who come into contact with the water while swimming or taking part in leisure activities. Shellfish and fish can also be contaminated if they are harvested from polluted coastal areas.

Reduced access to safe bathing waters

Sewage spills and chemical pollution often lead to warnings or temporary closures of beaches and designated bathing sites. This limits opportunities for exercise and recreation and adds cost and uncertainty for coastal communities that rely on visitors.

Impacts on local businesses

Tourism, water sports operators and hospitality venues near rivers and the coast can all be affected when water quality falls. Poor environmental performance damages local area reputations, reducing visitor numbers and tourism revenues

Loss of community trust

When pollution events are frequent or poorly explained, confidence in water companies declines. People expect the areas where they live to be protected. Ongoing problems with sewage spills undermine that expectation and raise concerns about how money paid through domestic and business water bills is being used.

How the water sector is trying to reduce its environmental footprint

Although recent performance has raised concern, the water sector has several programmes focused on reducing its impact on the environment. These initiatives aim to cut emissions, limit pollution and improve the resilience of water supplies.

Net zero commitments

Water companies have set targets to lower the energy they use to treat and move water. Many are increasing green business energy use, improving pump efficiency and capturing biogas from sewage treatment. These changes are expected to reduce carbon emissions across the network.

Pollution reduction and monitoring

Investment plans include upgrades to treatment works, new storage capacity for storm flows and better maintenance of sewer networks. Companies are also installing more monitoring equipment at discharge points, so they can respond faster when issues occur. The aim is to reduce both the frequency and the impact of spills.

Innovation and smarter ways of working

New technology and AI adoption is being introduced to increase efficiency. Examples include digital network monitoring, leakage reduction tools and treatment processes that remove more pollutants. Some companies are also exploring water reuse to reduce pressure on abstraction during dry periods.

Supporting customers to use less water

Reducing demand helps cut emissions and improves water availability, especially during dry periods. Water companies promote water efficiency for homes and businesses through practical devices, advice and targeted programmes in high-risk areas.

Smart water meters are increasingly being installed to give customers real-time visibility of how much water they use. This makes it easier to spot leaks, change habits and understand the impact that small daily choices can have on overall consumption.

What can I do to reduce the environmental impact of my water supply?

Using water more efficiently is one of the most effective ways to lower your environmental footprint. When consumption is lower, less energy is needed to pump and treat water, and more water stays in the environment during dry periods. Simple steps at home or in your business can make a real difference when they are repeated at scale.

Easy changes you can make today

Small habits help reduce water use without much effort. Try turning off the tap while brushing your teeth or washing dishes. Take shorter showers rather than filling a bath. Wait until the dishwasher or washing machine is full before switching it on. Fix any dripping taps or running toilets quickly to avoid wasting many litres over time.

Smarter use in kitchens, bathrooms and gardens

Much of the water we use every day goes straight down the drain. Choosing efficient shower heads, taps, and toilets cuts the amount of water needed with no noticeable difference to comfort. In gardens, rainwater harvesting systems or a simple water butt can replace mains water for plants and outdoor cleaning.

Longer-term improvements

Some upgrades involve a little more planning but deliver ongoing benefits. Greywater systems can reuse water from showers or sinks for garden watering, where safe and appropriate. Regular water leak checks inside and outside the property prevent avoidable losses. Businesses can improve efficiency by reviewing water use in kitchens, toilets and processes and by choosing efficient appliances when equipment is replaced.

Green business water suppliers

Some business water suppliers now offer greener services that aim to lower the environmental impact of water use. To balance the emissions created from treating and transporting water, a green business water supplier invests in carbon credits to offset the emissions associated with water and wastewater.

Find out more in our guide to sustainable water supplies for businesses.

Why it matters

Every litre saved reduces the amount of energy used to treat and move water. It also lowers stress on rivers and groundwater, especially during hot and dry periods. Collectively, these small actions help cut emissions and protect the natural environment.

Understanding your water footprint can make it easier to see where most water use happens and where small changes can have the biggest impact.

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