New techniques enable a shift in monitoring chemicals that affect water quality from mainly at the end product, tap water, towards monitoring during the whole process along the production chain. This is congruent with the 'HACCP' system (hazard analysis of critical control points) that is fairly well integrated into food production but less well in drinking water production. This shift brings about more information about source quality, the efficiency of treatment and distribution, and understanding of processes within the production chain, and therefore can lead to a more pro-active management of drinking water production. At present, monitoring is focused neither on emerging chemicals, nor on detection of compounds with chronic toxicity. We discuss techniques to be used, detection limits compared to quality criteria, data interpretation and possible interventions in production.