8.2.   Drinking water



Approximately 900 million m3 water is abstracted in Denmark each year, approx. 300 million m3 being abstracted by the agricultural sector and approx. 600 million m3 by the waterworks. Of the latter, 98-100% is derived from groundwater and 0-2% from surface water. Consumption of waterworks water is shared roughly equally by consumers and industry/institutions. The average Dane thus uses approx. 60 m3 tap water per year for household purposes. Abstraction is undertaken by approx. 350 municipal waterworks (together accounting for 60% of waterworks production), 3,000 private waterworks (together accounting for 40% of waterworks production), as well as just over 100,000 individually owned abstraction wells and a number of industrial wells and field watering wells.

The EC sets precise requirements as to the quality of drinking water through Directive 75/440 on water supplies based on surface water and Directive 80/778 on water supplies based on groundwater. The majority of the requirements are founded on health considerations and are based on the work of the WHO. The requirements concerning pesticide residues are founded on the premise that pesticides are undesirable in drinking water. The requirements are directed at the waterworks and at food processing enterprises. The requirement of most significance in Denmark is the limit level for nitrate of 50 mg/l.

The limit levels in the EC Directives have been implemented almost unchanged in Danish legislation.

The rules have led to the closure of a number of waterworks abstraction wells in the sandy soils of Jutland on the grounds that the nitrate level exceeded the limit level of 50 mg/l.

In recent years a number of waterworks abstraction wells have also been closed because of too high concentrations of organic solvents derived from industrial activities. This is related to the problem of contaminated land, as reviewed in Chapter 10.

In the last few years, especially since 1994, Denmark has become aware that pesticide pollution of the groundwater has become an environmental problem of considerable magnitude. The limit level is 0.1 µ/l for each pesticide, which corresponds to the detection limit at the time the rules were drawn up. The limit level for the total pesticide content is 0.5 µ/l. In 1994 the waterworks investigated approx. 2,000 water abstraction wells for pesticide residues. One or more pesticides were found in 14% of the wells, with limit levels being exceeded at 3%12. The pattern of pollution has not yet been elucidated, but certain of the substances occur frequently in the analyses undertaken; this is the background for the recent prohibition of certain pesticides (see Section 9.4).


Trend in groundwater nitrate content in Denmark (1940-84)

The EC rules do not apply to individually owned water abstraction wells. Denmark has nevertheless chosen to apply the same limit levels to the wells as apply to waterworks water. Originally it was believed in Denmark that this was in accordance with the EC rules. However, despite a 1991 EC court ruling that the EC rules did not in fact apply to individually owned abstraction wells, Denmark decided to keep the rules in force.


Groundwater nitrate content in contain vulnerable agricultural areas in Jutland(19980-93)

The reason for taking that line in Denmark is the desire to ensure that supplies of drinking water of a completely satisfactory hygienic standard are available to the population in the long term.

There is no clear pattern of municipal supervision of the water quality of individually owned abstraction wells. Sometimes the water is analysed when the property changes hands, other times in connection with plans to expand a waterworks supply net. Experience shows that when such analyses are undertaken, approx. 70% of the abstraction wells are found to have too high levels of nitrate, bacteria or other substances. If the Municipality then draws up an overall plan it can, with the approval of the County, force the properties in question to be connected to the waterworks supply net. Those properties whose water is of poor quality do not receive compensation, while those whose water quality is good receive compensation for the value of the abstraction well. In any case, all the properties in question have to pay to be connected to the supply net, and if the water pipe is long, the price can run up to DKK 50-60,000 per property. Such actions by the Municipalities are not particularly popular! Those affected often consider it as custodialism that the authorities meddle in what type of water they drink.


Occurrences of pesticides in groundwater in monitoring areas during the period 1989-92

The general rule is that the individual landowner has the right to abstract groundwater on his own land for use in his household. However, the rule does not apply if the property lies within an area supplied by a waterworks, or if there is an obvious danger that the quality of the water cannot meet the requirements.

As a rule it is the County that decides whether water abstraction can be permitted. The Counties thus deal with cases concerning both waterworks abstraction wells, industrial abstraction wells and field watering abstraction wells.

Since 1980, nearly all field watering using water pumped directly from watercourses has been stopped. As the old permits run out - they usually last 10 years - farmers have been advised to construct an abstraction well at a suitable distance from the watercourse (in order to avoid taking water from the watercourse during the driest time of the year).

Progress on the regulation of drinking water should be evaluated from the viewpoint that Danes are accustomed to having good quality water produced from groundwater, and that the aim is to be able to continue to do so. It has so far proved possible to fulfil this aim.