Protection of drinking water resources from PMT/vPvM substances: Revised guidance for ⁠REACH⁠ registrants on the identification of these substances of very high concern (SVHC). Only 1.9 % of the unique chemical structures in the REACH registration database fall in the new ⁠CLP⁠ hazard classes PMT and vPvM. However, for a total of 64 % no final assessment was achieved, either due to lack of test data (41 %) or due to ambiguous assessment (23 %). These guidance and methods can be used immediately by REACH registrants to ensure the safety of their substances, to close data gaps and, if necessary, to use safer alternatives, or to implement risk mitigation measures (RMMs).