Research and analysis

State of the water environment indicator B3: supporting evidence

Updated 22 May 2025

Applies to England

In the 25 Year Environment Plan, water theme indicators are:

• B1. Pollution loads entering waters
• B2. Serious pollution incidents to water
• B3. State of the water environment
• B4. Bathing waters
• B5. Water bodies achieving sustainable abstraction criteria
• B6. Naturalness of water
• B7. Health of freshwaters assessed through fish populations

Related indicators for water use, quantity and availability are:

• E8. Efficient use of water
• F3. Disruption or unwanted impacts caused by drought

F3 is also an indicator within resilience to natural hazards.

Indicators within managing exposure to chemicals and minimising waste are:

• H3. Emissions of mercury and persistent organic pollutants to the environment
• H4. Exposure and adverse effects of chemicals on wildlife in the environment
• J5. Prevent harmful chemicals from being recycled

This evidence summary supports the B3 state of the water environment indicator.

State of the water environment in England: data summary

All surface waters

16% of assessed surface waters and 79% of individual tests achieve good ecological status.

Rivers

14% of rivers and 77% of individual tests achieve good ecological status.

Biology

Fish (2022): 43% at good status.

Invertebrates: 76% at good status.

Macrophytes and phytobenthos: 45% at good status.

Physical modification

Rivers including canals: 58% support good status.

Water quality

Dissolved oxygen: 82% at good status.

Ammonia: 92% at good status.

Phosphorus: 45% at good status.

Hazardous substances

Chemical status: 0% at good status.

Chemical status excluding ubiquitous, persistent, bioaccumulative, toxic substances (uPBTs): 93% at good status.

Lakes

14% of assessed lakes are at good ecological status.

Biology

Phytoplankton: 52% at good status.

Macrophytes and phytobenthos: 29% at good status.

Physical modification

51% support good status.

Water quality

Total phosphorus: 25% at good status.

Total nitrogen: 45% at good status.

Hazardous substances

Chemical status: 0% at good status.

Chemical status excluding uPBTs: 100% at good status.

Estuaries

19% of assessed estuaries are at good ecological status.

Biology

Fish: 77% at good status.

Invertebrates: 67% at good status.

Saltmarsh: 36% at good status.

Seagrass: 90% at good status.

Eutrophication (2022) combined assessment

Rating	Certain there is no problem	Uncertain there is a problem	Quite certain there is a problem	Very certain there is a problem	Total
Percentage	43%	41%	13%	3%	100%

Hazardous substances

Chemical status: 0% at good status.

Chemical status excluding uPBTs: 92% at good status.

Physical modification (2019)

50% support good status.

Coastal waters

45% of assessed coastal waters are at good ecological status.

Biology

Invertebrates: 87% at good status.

Saltmarsh: 50% at good status.

Seagrass: 83% at good status.

Eutrophication (2022) combined assessment

Rating	Certain there is no problem	Uncertain there is a problem	Very certain there is a problem	Total
Percentage	71%	27%	2%	100%

Hazardous substances

Chemical status: 0% at good status.

Chemical status excluding uPBTs: 100% at good status.

Physical modification (2019)

74% support good status.

Groundwater

Quantity: 73% at good status.

Quality: 45% at good status.

Drinking water protected areas

Surface water (2022)

47% not at risk of deterioration.

Groundwater (2019)

53% not at risk of deterioration.

Designated bathing waters (2024)

An increase of 27 new bathing water designations must be considered when comparing 2024 and 2023 classifications.

Status	Excellent	Good	Sufficient	Poor	Total
Percentage	64%	21%	6%	8%	100%

Shellfish waters (2023)

Based on 2023 data of 72 assessed shellfish water protected areas, out of 101 designations.

Status	Pass	Fail	Total
Percentage	29%	71%	100%

Protected nature sites (2022)

Condition	Favourable	Unfavourable recovering	Unfavourable no change	Unfavourable declining	Total
Percentage	45%	43%	6%	6%	100%

About the data

Figures are percentages of water bodies assessed; where referred to as ‘at good status’, this is good or better status and potential. Non-integer numbers are rounded down to the nearest whole number.

For percentage figures supporting good status and potential under physical modification, this data is taken from the Reasons for Not Achieving Good (RNAG) dataset (March 2019).

Not all indicators update annually: unless more recent data is available as stated, all data was sourced 2019.

Hazardous substances: uPBTs are substances that are ubiquitous, persistent, bio-accumulative and toxic.

The 2019 WFD water body classification data is available on data.gov.uk.

For other data contact enquiries@environment-agency.gov.uk

Surface waters: ecological and chemical classification

Ecological status

Ecological status is assigned using various water, habitat and biological quality tests. Failure of any one individual test means that the whole water body fails to achieve good or better ecological status or potential (the ‘one out all out’ rule).

The ‘State of the water environment in England: data summary’ section shows data for each surface water type – representative elements that are tested to assess the condition of the water body, reflecting water quality and hydromorphology.

Ecological status is measured in 5 classes (bad to high).

2019 classification results show surface water ecological status has remained stable and 16% of surface water bodies achieved good or better ecological status or potential, the same as in 2016.

Classification	Description	Percentage in status
High	Natural or almost natural state with no, or only minor evidence of distortion.	Less than 1%
Good	Slight change from natural state as a result of human impact.	16%
Moderate	Moderate change from natural state as a result of human impact.	63%
Poor	Major change from natural state as a result of human activity.	17%
Bad	Severe change from natural state as a result of human activity.	3%

Chemical status

Chemical status is calculated by assessing 52 different chemical elements (individual and groups of chemicals). Water bodies are classified as good or failing.

For 2019 chemical classifications, new assessments for uPBTs were included, as well as new standards, improved techniques and methods.

This resulted in 0% surface water bodies meeting the criteria for achieving good chemical status in 2019, compared to 97% pass in 2016.

If we exclude the new assessments for uPBTs then only 6.2% of surface water bodies fail the chemical tests and 93.8% pass.

Current data is shown as ‘Hazardous substances’ in the ‘State of the water environment in England: data summary’ section. This shows the water body results for rivers, lakes, estuaries and coasts for chemical status with and without the uPBTs.

The 2019 water body classification data is published on data.gov.uk.

Check how to find information in the 2022 update to the river basin management plans.

You can use the Catchment Data Explorer to find and download data.

New monitoring approach and data for future reporting

Under our previous approaches to monitoring and reporting the state of the water environment, it has proven challenging to separate out the evidence of environmental change over time from the targeted monitoring evidence designed to identify pressures and solutions. In addition, we have not been measuring some aspects of the water environment which are anticipated to change, or which are important in providing goods and services on which the economy and people rely.

As a result, we were missing vital information required to measure progress against and meet the dual aspiration in the Defra 25YEP/EIP23 of improving the environment whilst ensuring it continues to support the economy. 

A fresh approach to assessing change in the water environment is needed. To enable us to do that, the government has funded the Natural Capital and Ecosystem Assessment programme (NCEA). The NCEA will design and deliver an unbiased and holistic view of the state of our water environment, how it changes over time and the benefits it provides society.

The NCEA programme is delivering a set of national scale surveillance monitoring networks that will enable us to assess the state of and trends in the water environment over time. These networks complement our pressure-specific local monitoring programmes, allowing us to track and evaluate national-scale changes to the water environment.

New water surveillance networks include: rivers, groundwater, small streams, lakes, river temperature, estuaries and coasts. In addition, we are trialling innovative techniques and methodologies, including eDNA and acoustic monitoring. 

The NCEA programme will develop indicators and metrics to assess the capacity of the water environment to deliver benefits to society, and how these are affected by changes to the state of our water environment.

The data and evidence from these new networks will be included in 25 YEP/EIP23 reporting on the state of the water environment in future.

This is a large and complex programme which is taking time to develop and phase in over the next few years.

Developing natural capital indicators to sustainably manage the water environment

A healthy water environment provides many goods and services which benefit people and the economy (such as clean water, flood protection or places for recreation). However, we are lacking information about the importance of the water environment to society which, if available, would help us understand the trade-offs between the state of the environment and the benefits derived from it, helping us to manage the environment sustainably, ensuring it continues to support people and the economy.  

Natural capital indicators address this gap by focussing on the contribution of the environment to society and the economy, including:

• The state of the environment and its ability to provide goods and services
• The benefits gained by society, who benefits, and the value of those benefits
• The risks to flows of goods and services caused by changes in natural assets, and the consequences to people and the economy

Natural capital indicators are being developed to complement traditional ways of reporting on the state of the water environment. In addition, we can put existing indicators in a natural capital context (see next topic) so we can better understand the impact and consequences to society of changes in the state of the water environment.  

In many cases natural capital indicators can be developed from existing monitoring data. However, in some cases they will require a shift to monitoring those properties of the environment which are most closely related to their ability to deliver services to people (e.g. extent of active floodplain contributing to flood protection), or will involve combining environmental, social and economic data (e.g. to assess the improvements in physical and mental health of people using bathing waters).

Natural capital indicators: physical modification of rivers

A large proportion of our lowland rivers have been straightened, dredged or enclosed in a culvert for reasons that include creating larger, better drained fields for agriculture, reducing flood risk, and making space to build homes or roads. These changes in the morphology of the river channel and surrounding vegetation have detrimental consequences for wildlife that live in and around the river. We assess this level of morphological change and report it through the Water Framework Directive as ‘percentage of rivers supporting good status and potential, in relation to morphological condition.’

We can develop natural capital indicators that tell us about the consequences of river morphology for the river ecology and the subsequent benefits to people. The more natural a river’s morphology, the more the river can support diverse and resilient plant and invertebrate ecological communities, which in turn support higher fish stocks and produce more water purification ecosystems service. These provide benefits to people, including opportunities for recreation, fishing, lower water treatment costs, some of which can be valued. By taking into account these benefits when deciding how to maintain the river we can manage it to maximise benefits for both wildlife and society.

Groundwater: ecological and chemical classification

Nitrate is the most common cause of groundwater test failure.

	2015	2019
Failure of trend test due to nitrate	25.5%	26.9%
Failure of any test due to nitrate	36.9%	39.8%

Groundwater quantitative classification

Net increase in the number of groundwater bodies meeting good quantitative status.

Year	Poor	Good	Total
2009	40%	60%	100%
2015	31%	69%	100%
2019	27%	73%	100%
2022	27%	73%	100%

Groundwater chemical classification

Net decrease in the number of groundwater bodies meeting good chemical status.

Year	Poor	Good	Total
2009	42%	58%	100%
2015	47%	53%	100%
2019	55%	45%	100%

Substances causing failure for 2019 across all tests and groundwater bodies

Substance	Test failure figure
Nitrate	108
Orthophosphate	36
Copper	35
Chloride	35
Zinc	34
Sulphate	34
Iron	34
Manganese	33
Nickel	22
Ammoniacal nitrogen	14
Solvents	12
Lead	11
Electrical conductivity	9
Aluminium	9
Pesticides	8
Cadmium	8
Arsenic	8
Boron	6
Sodium	3
Other metals	2
Mecoprop	2
Hydrocarbons	2
Bromate	2
Polycyclic aromatic hydrocarbons (PAHs)	1
Per- and polyfluoroalkyl substances (PFAS)	1
Fluoride	1
Chromium	1
Antimony	1

Groundwater classification status and objectives data is published on data.gov.uk.

Drinking water protected areas

Reservoirs, lakes, rivers and groundwater, from which raw water is abstracted for human consumption at a rate of 10 m³ per day or more or serving more than 50 people are Drinking Water Protected Areas (DrWPAs). These criteria are defined in the Water Environment (Water Framework Directive) (England and Wales) Regulations 2017. Safeguard zones are areas connected to the DrWPA where pollution needs to be reduced to protect the drinking water resource.

For surface water DrWPAs the safeguard zones cover the upstream catchment areas which can include more than one DrWPA. For groundwaters the DrWPA is a large underground aquifer which may include multiple safeguard zones to protect springs or boreholes.

Safeguard zones can cover more than one pollutant type and are established when raw water quality is deteriorating, or is likely to deteriorate in the future (that is ‘at risk of deterioration’). Measures aiming to avoid deterioration, reducing the level of water treatment required to produce drinking water, are set out in Safeguard Zone Action Plans.

Surface water

There are 450 surface water DrWPAs.

There are 240 at risk of deterioration.

There are 148 surface water safeguard zones.

Reasons for establishing surface water safeguard zones:

• pesticides: 50%
• sediment: 22%
• algae: 19%
• nitrate: 5%
• microbiology: 2%
• other: 2%

Groundwater

There are 271 groundwater DrWPAs.

There are 127 at risk of deterioration.

There are 251 groundwater safeguard zones.

Reasons for establishing groundwater safeguard zones:

• nitrate: 73%
• pesticides: 13%
• solvents: 8%
• microbiology: 3%
• sediment: 1%
• other: 2%

European protected nature sites for water and wetlands

Underlying SSSI unit condition by habitat

Rivers

Condition	Favourable	Unfavourable recovering	Unfavourable no change	Unfavourable declining	Total
Percentage	9.9%	51.3%	36.6%	2.2%	100%

Lakes

Condition	Favourable	Unfavourable recovering	Unfavourable no change	Unfavourable declining	Total
Percentage	58.8%	13%	19.9%	8.3%	100%

Estuaries and coasts

Condition	Favourable	Unfavourable recovering	Unfavourable no change	Unfavourable declining	Total
Percentage	59.4%	31.9%	2.6%	6.1%	100%

Wetlands

Condition	Favourable	Unfavourable recovering	Unfavourable no change	Unfavourable declining	Total
Percentage	13.3%	73.2%	10.4%	3.1%	100%

Condition change: all SSSI units underlying water-dependent habitats

Favourable:

• 240,179 hectares (ha)
• 45%

Unfavourable recovering:

• 229,298ha
• 43%

Unfavourable no change:

• 29,860ha
• 6%

Unfavourable declining:

• 32,229ha
• 6%

About the data

This data on European protected nature sites for water and wetlands:

• includes rivers, lakes, wetlands, estuaries and coasts, and other water-dependent habitats
• includes sites designated for birds that may be in favourable condition without assessment of water quality
• excludes adverse condition reasons that are unrelated to Water Framework Directive drivers
• was retrieved in November 2022
• is a derived analysis, not a published dataset

For more information on this data contact Natural England.

Key issues and sectors affecting water bodies in England

Sector	Physical modifications	Pollution from waste water	Pollution from towns, cities and transport	Changes to natural flow and levels of water	Non-native invasive species	Pollution from rural areas	Pollution from abandoned mines
Agriculture	12.9%	0.1%	0.1%	1.3%		40%
Industry	1.9%	0.5%	3.4%	0.4%
Mining and quarrying	0.1%		0.1%				3.2%
Navigation	1.9%			0.1%
Urban and transport	10.9%	0.6%	10.1%
Water industry	7.9%	35%	0.8%	9.8%
Local and central government	14.3%	0.2%		0.2%
Domestic general public	0.3%	1.1%	6.4%
Recreation	2.9%		0.2%	0.1%
Waste treatment and disposal		0.1%	0.3%
No sector responsible	0.1%		0.1%		23%

Percentage of water bodies impacted by each issue

Issue	Percentage of water bodies impacted
Physical modifications	41%
Pollution from waste water	36%
Pollution from towns, cities and transport	18%
Changes to natural flow and levels of water	15%
Non-native invasive species	23%
Pollution from rural areas	40%
Pollution from abandoned mines	3%

Percentage of water bodies impacted by each sector

Sector	Percentage of water bodies impacted
Agriculture	45%
Industry	6%
Mining and quarrying	3%
Navigation	2%
Urban and transport	18%
Water industry	44%
Local and central government	14%
Domestic general public	8%
Recreation	3%
Waste treatment and disposal	0.3%
No sector responsible	23%

Sectors and challenges preventing good water quality in England

Most of the data used to produce the tables in the ‘Key issues and sectors affecting water bodies in England’ section are taken from the 2019 set of probable and confirmed reasons for not achieving good status (RNAGs), linked to 2016 WFD classifications. This is with the exception of the following:

1. Changes to the natural flows and levels of water. The data are for those water bodies that do not have sustainable levels of abstractions. The sector contributions include suspected, probable and confirmed RNAGs.

2. Invasive non-native species. This uses Environment Agency monitoring data and are for water bodies that have specific invasive non-native species present which we consider to be contributing to the water body not achieving good ecological status.

‘No sector responsible’ covers those situations where it is not possible to assign the failure to achieve good status to the activities of a specific sector. We have used this category mainly for invasive non-native species. Whilst the speed of their spread can be increased by poor practice, it is not possible to say whether their presence in a particular water body is ‘natural’ or due to someone’s actions.

Around 6% of water bodies have one or more RNAGs where the sector responsible is still under investigation. Around 5% of water bodies have one or more RNAGs caused by a different sector to those listed in the table. These are mainly where the issue is physical modification.

For more information on this data please contact the Environment Agency.

Further reports supporting river basin management plans: River Basin Planning: Challenges for the water environment

Long-term trends in river water quality

The Harmonised Monitoring Scheme (HMS) network provides a reliable and consistent data set for assessing how the water quality of England’s principal rivers has changed over time. In 2024, new analysis across 135 HMS sites in England has been conducted on data dating back from 1980 for river concentrations of nutrients, ammonia and biochemical oxygen demand (BOD), and river concentrations of dissolved metals dating back to 1990. Though the network extends before this, data is more variable before 1980/90. Pollution incidents are also excluded, giving a focus on longer term trends in water quality. 

All dissolved metals and many concentrations of these components indicative of water quality have substantially reduced over the period 1990 to 2023: arithmetic mean ammonia concentrations have reduced by 85%, and orthophosphate concentrations by 83%. Concentrations have continued to decrease in the period from 2000 and from 2010, though some have also risen.

For further component results and graphics, see the full report.

Figure 1. The locations of the 135 HMS sites in England included in the analysis. One site on the River Carnon was excluded in the calculation of concentrations for metals.