Diffuse pollution is the result of several sources of pollution from across a large area, which individually would have little impact, collectively causing significant environmental damage.

In 2010 SEPA surveyed farms across the River South Esk catchment for compliance with the General Binding Rules. More than 600 km of watercourses were walked. 150 farm visits were then conducted whereby advice was provided on modifying farming practices to reduce diffuse pollution. Farms were then revisited and ~95% were found to be compliant.