Statistical Office of the European Commission (Eurostat)

Unit E2: Environmental statistics and accounts; sustainable development

e-mail contact : ESTAT-SDI-EU2020-INDICATORS@ec.europa.eu

The indicator is part of the EU Sustainable Development Goals (SDG) indicator set. It is used to monitor progress towards SDG 6 on clean water and sanitation and SDG 15 on protecting, restoring and promoting sustainable use of land.

Among other things, SDG 6 calls for ensuring universal access to safe and affordable drinking water, sanitation and hygiene, and ending open defecation. It also aims at improving water quality and water-use efficiency and encouraging sustainable abstractions and supply of freshwater. SDG 15 seeks to protect, restore and promote the conservation and sustainable use of terrestrial, inland water and mountain ecosystems.

Indicator can be considered as similar to global SDG indicator 6.3.2 "Proportion of bodies of water with good ambient water quality".

Protection of water resources, water ecosystems and of drinking and bathing water is at the cornerstone of EU environmental policy, as confirmed in the 7th Environment Action Programme. EU water policy provides a framework to comprehensively address water protection and for achieving good status for inland surface waters, transitional waters, coastal waters and groundwater.

Biochemical oxygen demand (BOD) is used to measure water quality. It refers to the amount of oxygen required by aerobic microorganisms to decompose organic substances in a water sample over a period of five days in the dark at 20°C (BOD5), measured as milligrams per litre (mg O₂/L) and weighted by the number of measuring stations.

High values of BOD5 are usually a sign of organic pollution, which affects the water quality. The cleanest rivers have BOD5 values of less than 1 mg O₂/L., moderately and heavily polluted rivers show values ranging from 2 to 8 mg O₂/L.

Only complete series after inter/extrapolation are presented. Complete series 2000 – 2015 are based on a total of 1082 measuring stations distributed over the following countries (number of stations in parentheses): Austria (48), Belgium (36), Bulgaria (91), Croatia (40), Cyprus (4), Czechia (19), Denmark (4), Estonia (51), Finland (6), France (245), Ireland (54), Italy (73), Lithuania (24), Luxembourg (3), Latvia (21), Poland (103), Romania (115), Slovakia (18), United Kindom (81), Albania (8), Bosnia and Herzegovina (19) and North Macedonia (19).

mg O₂ per litre.

Calendar year.

The indicator is relative robust in presenting the overall trend and spatial variation in water quality.

For assessment of accuracy please refer to the original source (see link to external data source and metadata in section “Annexes”).

EEA (Waterbase database)

Data source: EEA Waterbase database on the status and quality of Europe's rivers.

Data provider: European Environment Agency (EEA)

Every year

Indicator is updated annually.

Not Available

Timeliness of indicator dissemination is not specified.

< 75% EU MS or no EU aggregate

Data are presented for all EU Member States except Germany, Greece, Spain, Hungary, Malta, the Netherlands, Portugal, Slovenia & Sweden; plus the United Kingdom, Albania, Bosnia and Herzegovina and North Macedonia.

< 75% EU MS

The data for the reporting countries are only comparable within the limits of the weighting of the different number of samples per country.

Furthermore, most countries measure organic matter as BOD over five days but a few countries measure BOD over seven days, which may introduce a small uncertainty in comparisons between countries.

> 10 years

Presented time series starts in 2000.

> 4 data points

Length of comparable time series without methodological break is longer than 4 data points.

Analysis of indicator is presented in Eurostat's annual monitoring report on Sustainable development in the EU (progress towards SDGs in the EU context).

See table  sdg_06_30

Eurostat dedicated section on SDGs: http://ec.europa.eu/eurostat/web/sdi/overview

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