B2: Serious pollution incidents to water
Short Description
This indicator shows changes in the number of pollution incidents impacting on water health, including in rivers, lakes, reservoirs, canals, coasts, estuaries and groundwater. Serious pollution incidents are a pressure on the water environment. The Environment Agency uses 4 categories to determine the severity of pollution incidents. The indicator shows the number of events in each year that are in the 2 higher categories (category 1, major and category 2, significant), for example, causing death of fish, potential harm to bathers, or the temporary cessation of abstraction from a river by a drinking water provider.
Readiness and links to data
Data are already published annually by the Environment Agency, through the:
- Environmental Pollution Incidents (Category 1 and 2)
- Water and sewerage companies in England: environmental performance report 2023
Longer-term trends are available in the State of the environment: water quality report and the Environment Agency Chief Regulator’s report 2023-24.
Notes on indicator
Some incidents may take an extended period of months, or exceptionally years, to be completed. The dataset only includes substantiated incidents and their environmental impact, that is where there is confirmation that the incident took place either by a visit from the Environment Agency or a partner organisation, or it is corroborated by other information. Results do not include incidents relating to:
-
fisheries incidents – incidents involving illegal fishing and illegal fish movements, fish disease, fishery management activities and fish kills from non-pollution causes, including low flows and low dissolved oxygen
-
water resources incidents – incidents involving the quantity of a water resource
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waterways incidents – incidents on a waterway where the Environment Agency are the competent authority for navigation
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flood and Coastal Risk Management incidents – for incidents which involve actual or potential flooding and land drainage works
Indicator components
Figure B2: Serious pollution incidents to water in England, 2001 to 2023
Table B2: Serious pollution incidents to water in England, 2001 to 2023
| Year | Category 1 (Major) incidents | Category 2 (Significant) incidents |
|---|---|---|
| 2001 | 98 | 736 |
| 2002 | 76 | 693 |
| 2003 | 83 | 618 |
| 2004 | 83 | 505 |
| 2005 | 73 | 495 |
| 2006 | 75 | 461 |
| 2007 | 56 | 380 |
| 2008 | 59 | 314 |
| 2009 | 66 | 361 |
| 2010 | 43 | 294 |
| 2011 | 41 | 320 |
| 2012 | 41 | 250 |
| 2013 | 43 | 324 |
| 2014 | 53 | 307 |
| 2015 | 51 | 274 |
| 2016 | 51 | 266 |
| 2017 | 42 | 220 |
| 2018 | 69 | 245 |
| 2019 | 41 | 225 |
| 2020 | 47 | 270 |
| 2021 | 47 | 282 |
| 2022 | 43 | 264 |
| 2023 | 56 | 322 |
Trend description for B2
The total number of serious pollution incidents to water in England fell by 54.7% between 2001 and 2023, with the majority of this decline occurring in the first 10 years (from 834 in 2001 to 337 in 2010). From 2010 to 2017, while there were annual fluctuations in the number of category 1 (major) and category 2 (significant) pollution incidents, the overall trend largely plateaued. More recently however, the number of serious pollution incidents increased to 378 (56 major and 322 significant) in 2023, the highest figure since 2009.
Assessment of change
There has been a decrease in serious pollution incidents (i.e. an improvement) over the long term, and an increase (deterioration) in the medium term and short term. This assessment does not consider whether any improvements seen are on a sufficient scale for meeting desired outcomes.
Change since 2018 has also been assessed, showing an increase (deterioration) in serious pollution incidents over this period.
Further information on this assessment, along with details on the methodology, is provided in the Assessment background. Summaries by 25 Year Environment Plan goal and information on indicator links are presented in the Assessment results.
Table B2: Assessment of change
| Component | Subcomponent | Period | Date range | Percentage change | Smoothing function | Assessment of change |
|---|---|---|---|---|---|---|
| B2 | Serious pollution incidents | Short term | 2018 to 2023 | 16.72 | Loess | Deterioration |
| B2 | Serious pollution incidents | Medium term | 2013 to 2023 | 6.23 | Loess | Deterioration |
| B2 | Serious pollution incidents | Long term | 2001 to 2023 | -58.25 | Loess | Improvement |
Note that assessment categories for the short, medium and long term were assigned based on smoothed data, so percentage change figures in Table B2 may differ from unsmoothed values quoted elsewhere. Percentage change refers to the difference seen from the first to last year in the specified date range.