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The global water quality database GEMStat

The Global Water Quality database and information system GEMStat is hosted, operated, and maintained by the International Centre for Water Resources and Global Change (ICWRGC) in Koblenz, Germany, within the framework of the GEMS/Water Programme of the United Nations Environment Programme (UNEP), and in cooperation with the Federal Institute of Hydrology. GEMStat hosts water quality data of ground and surface waters providing a global overview of the condition of water bodies and the trends at global, regional and local levels.

At present, the growing database contains more than 18 million entries for rivers, lakes, reservoirs, wetlands and groundwater systems from 94 countries and more than 15,000 stations. Overall, data is available for the time period from 1965 to 2022 and more than 200 parameters (see data section for more information).

Countries and organisations voluntarily provide water quality data from their own monitoring networks. The water quality data available in GEMStat can be used for status evaluation, policy-making, research purposes or within the scope of education and training initiatives.

Download our flyer with all relevant
information on GEMStat:

Flyer (English)
Flyer (French)
Flyer (Spanish)

Download, PDF, 2.p, 417 KB

The GEMS/Water-Programme

The Global Environment Monitoring System for Freshwater (GEMS/Water) is a programme that aims at collecting world-wide freshwater quality data to support scientific assessments and decision-making processes. In addition, GEMS/Water offers support and encouragement to developing countries wishing to establish monitoring programmes and conduct assessments of water quality, by providing capacity development via training, advice and assessment tools.

GEMS/Water was established in 1978 as an interagency programme under the auspices of the United Nations through the United Nations Environment Programme (UNEP), the World Health Organization (WHO), the World Meteorological Organization (WMO), and the United Nations Educational, Scientific and Cultural Organization (UNESCO). Until 2014, when it returned to UNEP, the programme has been implemented by the WHO at the National Water Research Institute (NWRI) in Burlington, Canada.

With the adoption of the Sustainable Development Goals (SDGs) and especially SDG 6 (“Clean Water and Sanitation”), the importance of water quality for human and ecosystem health has attracted renewed attention. In June 2014, the first UN Environment Assembly (UNEA) in Nairobi (Kenya) endorsed GEMS/Water as being one of the mechanisms to assist in achieving the SDGs. Special focus is on sub-target 6.3, aiming at improving water quality, and the corresponding indicator 6.3.2.

Collected in the GEMStat database, the data of GEMS/Water were managed by the Department of the Environment of Canada for more than 30 years, until March 2014. Since November 2014, GEMStat has been operated, hosted and maintained by the GEMS/Water Data Centre (GWDC) within the International Centre for Water Resources and Global Change (ICWRGC) in Koblenz, Germany.

Explore the objectives, elements and recent activities of GEMS/Water in an interactive Story Map:

Access Story Map

Today the GEMS/Water Programme comprises the following elements:

Capacity Development Centre, Ireland
Data Centre, Germany
Global Programme Coordination Unit, Kenya
  • Global Programme Coordination Unit (GPCU):
    Located in the Science Division at the UNEP headquarters in Nairobi, Kenya, the GPCU is responsible for the overall coordination of the GEMS/Water Programme and the maintenance of the GEMS/Water network of National and Collaborating Focal Points (NFPs and CFPs). Furthermore, it works with Regional Hubs and partners on designing water quality monitoring schemes, capacity development and assessments as well as providing services for policy making and water management.
  • GEMS/Water Data Centre (GWDC):
    Based on a treaty between UNEP and the German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety, the GWDC is located at the International Centre for Water Resources and Global Change (ICWRGC) in Koblenz. The GWDC hosts, maintains and coordinates the GEMStat database and information system. It also disseminates activities related to GEMStat data.
  • GEMS/Water Capacity Development Centre (CDC):
    Founded at the University College Cork in Ireland, the functions of the CDC are to develop a standardized approach to data generation by participating countries through providing guidance and training on all aspects of water quality monitoring and quality assurance of monitoring activities. The aim is to ensure the coherence of the GEMS/Water Programme and the compatibility and comparability of data for use in national, regional and global assessments.
  • Regional Hubs:
    At the regional level, several Regional Hubs are planned to support the GEMS/Water Programme in communicating with the partners and in implementing programme activities, especially in the field of capacity development in the individual regions.