Improving water quality is central to EU water policy. Over the years, many of Europe's rivers, streams, lakes and coastal waters have become polluted and water ecosystems have been affected by changes to our water courses, so the EU has measures to help return waters to their natural state.
The Commission receives regular reports on drinking water quality from Member States, and analyses them carefully. Most of the EU has excellent quality drinking water, although the situation is not quite so positive in rural areas.
Farms can be a major source of pollution, as fertilisers, manure and pesticides are regularly washed into rivers, streams and lakes. In the field they boost the growth of crops, but in water they can lead to a serious increase in algae. This reduces the oxygen level in the water, suffocating fish and other creatures. So strict controls are in place on what is spread on fields, and when.
Chemicals used to kill unwanted pests or plants can also have a devastating effect on water-dwelling plants and creatures. This is why aerial spraying is banned, and watercourses are protected by buffer zones.
Some industries produce substances that are damaging to the environment and human health, but strict laws and cleaner technologies have reduced water pollution caused by industry.
Most waste water is treated to remove organic matter, and a lot also gets disinfection or treatment to remove nutrients. But many areas of Europe still need to improve sewage collection and treatment.
Humans too can be a direct source of pollution. We use pharmaceuticals, and if they not disposed of properly, they can end up in soil, rivers and lakes, with harmful consequences for plants and animals.
But most EU bathing waters are now clean – and the percentage of freshwater bathing sites that qualify for the top category almost doubled between 1990 and 2009.