Groundwater researchers, Master and PhD students from globally leading environmental tracer laboratories and research institutes in Switzerland (Univ. Bern), Germany (Univ. Heidelberg, Univ. Bremen), the Netherlands (TNO), Denmark (GEUS) and Italy (Univ. Sapienza, Rome) met this week in the city of Odense, Denmark, in order to collect water samples for estimation of groundwater age distributions in water supply wells of VCS Denmark of which many are contaminated by pesticides. The work is part of the HOVER project within the GeoERA program of the European geological surveys, which is co-funded by the EU, European geological surveys and Innovation Fund Denmark. The sampling program included collection of samples for the analysis of the following important tracers: 85Kr, 39Ar, 37Ar, 3H/3He, 4He, 14C, d13C, 18O, 2H, SF6, CFCs and noble gases. In addition some wells were sampled for the analysis of pesticides and emerging contaminants. The research institutes benefited from the efficient and skilled support of groundwater specialists and technicians of VCS Denmark, which ensured efficient collection of 11 samples from 9 different water supply wells for water analyses to be conducted at five research laboratories and one commercial laboratory. All samples were collected in just 2.5 working day .