Drinking water in Denmark is produced exclusively from ground water. The exploitable resource is greater than the present abstraction but increasing contamination, climate variation and changes in land use may adversely affect the future ground-water resources. Changes in water quality are systematically being registered in the Danish ground-water monitoring programme, described in this paper. Ground-water quality in Denmark is generally good, but locally shallow aquifers are contaminated by nitrate, pesticides, heavy metals and in urban areas by organic micro-pollutants. The National Water Resource Model is under development for use as a tool for the assessment of the size and distribution of the future exploitable ground water resources.