Water UK

October 2007

Control of diffuse pollution at source

Sustainable solutions to problems of diffuse pollution can only be secured by control at source.
 

It is widely recognised that much of the remaining water pollution problem in the UK derives from diffuse rather than point sources.

Diffuse pollution arises from a variety of sources, including:

 • run-off from agricultural land
 • run-off from urban areas
 • use of chemicals in the home and by industry.

Diffuse pollution from agriculture, particularly from nitrates and pesticides, has imposed major cost and operational difficulty on water suppliers. In some areas the situation is continuing to deteriorate.

Trying to clean up diffuse pollution once it has been discharged into water or sewage:

 • is technically difficult and sometimes even impossible
 • requires very expensive and energy intensive processes
 • is invariably much more expensive than measures to prevent loss in the first place.

Thus requiring the water sector to deal with diffuse pollution through end of pipe solutions would:

 • be economically inefficient
 • create a massive increase in greenhouse gas emissions
 • be against all principles of sustainability and the WFD.

What this means for WFD implementation

 • It must be an over-riding principle of WFD implementation that diffuse pollution is dealt with by control at source and paid for by the sector responsible.

 • This applies particularly to non biodegradable substances discharged into sewers by industry and households.

 • Where pollutants such as P, which derive from multiple sources, need to be addressed, measures should initially be targeted on source control e.g. P in detergent or from land run-off.

 • Full use should be made of the technical infeasibility exemption provision when considering potential controls for non biodegradable substances at sewage works.

 • It is important that Article 7 of the WFD, which imposes a duty on member states to prevent deterioration that impacts on drinking water treatment, is properly implemented. If this is not done then further treatment to clean up water prior to supply to customers will be required in contravention of the WFD.

 
Supporting information
For PS use information from UKWIR report WW 17d/e
For Article 7 use information from Joint Water UK/EA survey