Pesticide occurrences in rivers may result from diffuse runoff from farmland or from point sources. The former is a possible outcome from usage on crops in a manner, which accords with ‘good agricultural practice’. The latter can arise from discharges to rivers from sewage treatment works or factories, accidental spills, deliberate disposal of surplus material into soakaways or rivers, poor application practices to crops close to rivers, amenity weed control leading directly to drainage systems, or vandalism. Diffuse inputs of pesticides into rivers are not easily reduced, since they are, by definition, physically dispersed. Also as they arise from ‘good agricultural practice’ reductions have to be achieved by alerting farmers and contractors to the issue and advising and persuading on the best ways to avoid waterpollution occurring. Point sources, although difficult to identify and locate, arise from poor management. As they can be reduced or eliminated by making changes to pesticide storage, handling and disposal, they are inherently more amenable to a regulatory approach by Environment Agency staff. A method of reviewing monitoring data to identify those occurrences arising from point sources would assist Agency staff in controlling pesticide pollution.