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.

Longer-term trends are available in the State of the environment: water quality report and the Review of activities regulated by the Environment Agency, 2022.

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.

  • Waterways incidents – incidents on a waterway where the Environment Agency are the competent authority for navigation.

  • 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 2022

Table B2: Serious pollution incidents to water in England, 2001 to 2022

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

Trend description for B2

The total number of serious pollution incidents to water in England has fallen by almost two-thirds (63%) between 2001 and 2022, with the majority of this fall occurring in the first 10 years (834 in 2001 and 337 in 2010). More recently, while there have been annual fluctuations in the numbers of category 1 (major) and category 2 (significant) pollution incidents in the last 10 years, the overall trend has plateaued, and in 2022, there were a total of 307 serious pollution incidents to water (43 major and 264 significant).

Assessment of change

A decrease in serious pollution incidents (or improvement) was observed over the medium and long term. However, as noted in the trend description, the percentage change seen over the medium term is much reduced compared with the long term and there are fluctuations year on year as can be observed in the short term trend with little to no change. 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, an improvement (a decrease in the number of incidents) has been observed. However, this result is based on only 5 data points so should be considered as indicative and not evidence of a clear trend.

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 2016 to 2021 -1.06 Loess Little or no change
B2 Serious pollution incidents Medium term 2011 to 2021 -11.77 Loess Improvement
B2 Serious pollution incidents Long term 2001 to 2021 -63.55 Loess Improvement

Note that assessment categories for the short, medium and long term were assigned based on smoothed data, so percent change figures in Table B2 may differ from unsmoothed values quoted elsewhere. Percent change refers to the difference seen from the first to last year in the specified date range.

Indicator Metadata