Overview
Groundwater is the water located in the saturation zone of the Earth's crust, which moves through soil pores or fractures under the influence of gravity or hydraulic pressure. In other words, if an underground layer of rock or sediment is saturated with water and it is possible to extract groundwater from this layer, then this underground layer of rock or sediment is called an aquifer.
- In Estonia, the volume of groundwater is estimated to be 2000 km³, and it is usable as drinking water and accessible almost everywhere.
Groundwater resources and balance
Groundwater resource refers to the quantifable volume of accessible water beneath Earth´s surface that can be used while maintaining optimal groundwater conditions. This assessment considers multiple critical factors, including the natural rate of water replenishment, the overall health of the aquifer system, and the long-term sustainability of the resource.
In Estonia the groundwater resource assessments become mandatory when daily extraction volumes exceed 500 cubic meters from an aquifer. This regulatory framework establishes a comprehensive oversight structure, with the groundwater commission serving as the primary review body for resource study reports, which ultimately receive ministerial approval through the Minister of Climate.
Groundwater balance reports (in Estonian):
Groundwater body status in Estonia
Estonia maintains 31 distinct groundwater bodies under regular monitoring, with comprehensive assessments conducted on a six-year cycle. The most recent assessmet of these water resources was carried out in 2020 by the Estonian Geological Survey, resulting in the following summary for Estonia:
- 23 groundwater bodies are in good status: 74%
- 8 groundwater bodies are in poor status: 26%
Groundwater pollution in Estonia stems from both natural processes and human activities. Natural contamination occurs through geological interactions, such as the mixing of deep Cambrian-Vendian Voronka aquifers with saltier water layers, which elevates chloride ion concentrations. Human-induced pollution, however, presents greater challenges through three primary sources: intensive groundwater extraction operations, extensive oil shale mining activities, and agricultural practices. These anthropogenic factors contribute significantly to excessive levels of various contaminants, including chlorides, sulfates, and ammonium, often surpassing acceptable thresholds in the groundwater system.
More information:
- The objectives for achieving optimal groundwater body status are outlined in European Parliament and Council Directive 2000/60/EC.
- Grounwater body status is assessed in Estonia acoording to the Guidance Document No. 18 under the Common Implementation Strategy for the Water Framework Directive
- The status of groundwater bodies can be examined in more detail using the map collection below and by reading the status assessment report from 2020 (in Estonian).
The status of groundwater bodies can be examined in more detail in the map story below.
Monitoring and nitrate vulnerable zones in Estonia
Estonia implements a comprehensive three-tier groundwater monitoring system:
- The quantitative monitoring network comprises approximately 245 stations, conducting measurements ranging from monthly to daily frequency (12-365 times annually) through both manual collection methods and automated water level sensors
- Chemical monitoring operates across roughly 230 stations, with annual sampling cycles featuring rotating hazardous substance assessments based on predetermined monitoring schedules
- Additionally, specialized monitoring programs focus on nitrate-vulnerable zones (NVZs) that consists multiple interconnected networks:
- The core monitoring network: 54 dedicated monitoring stations, monitored four times a year
- The support monitoring network: 58 monitoring stations, monitored once in a year
- Reference sampling quaterly from seven springs and seven wells located outside NVZ areas, providing valuable comparative data for monitoring effectiveness
The Estonian Environmental Research Centre (EKUK) oversees comprehensive groundwater monitoring operations, working within strict regulatory frameworks established by the Minister of the Environment's regulations no. 48 and 39. These regulations specify detailed parameter lists and criteria for each individual groundwater body.
EKUK maintains systematic documentation through annual summary reports compiled from collected monitoring data, which are subsequently archived in the Estonian environmental monitoring database KESE for public acces (in Estonia).
Overviews (in Estonian):
More information
- Borehole registry operations
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Answers to frequently asked questions about wells can be found on the Environmental Agency’s website (in Estonian).
A drilled well may be established by an entrepreneur or person holding the appropriate activity permit. Holders of permits for hydrogeological work.
For borehole registry operations, please contact customer support: @email