The purpose of these Regulations is to prevent the entry into groundwater of “hazardous substances” (defined as substances which are persistent, bio-accumulative or toxic) and the pollution of groundwater by “non-hazardous pollutants” (all other substances liable to cause pollution). The offence of discharging pollutants which might lead to an indirect input of such matter to controlled waters unless carried out in accordance with an authorisation granted by the Environment Agency, originally established in the Water Resources Act 1991 and incorporated in the 1998 Groundwater Regulations, is carried over in these Regulations, which cover both ‘direct’ (directly into groundwater) and ‘indirect’ (after percolation through soil and strata) inputs of pollutants to groundwater.