Following a request from the European Commission, the Panel on Plant Protection Products and their Residues (PPR) was asked to deliver a scientific opinion on the report of the FOCUS groundwater working group (FOCUS, 2009) with respect to lower tier leaching assessments. The PPR Panel is of the general opinion that the FOCUS groundwater working group has successfully harmonised major concepts in the leaching models and that, overall, the leaching estimations have improved. Despite several limitations, the PPR Panel considers that the revised FOCUS scenarios cover significant arable areas in the EU, including the New Member States, and allow for decision making at the EU level. The PPR Panel however has observed that flaws in underlying data have become apparent after finalising the report. Also new approaches on scenario selection have become available. The PPR Panel recommends that these flaws and new approaches are taken into account when developing revised scenarios.