There had been a huge improvement in our river water quality in the past decade because of measures against industrial and sewage pollution. But the new EU regulations will cover "diffuse pollution" in both town and countryside, which is not measured under present rules.
This includes run-offs from urban streets, over-abstraction to serve new building developments, and farm effluent from fertilisers, pesticides and sheep-dips.
Environment Minister Elliot Morley says that work must start now if the challenge of meeting the new 2015 standards are to be met because, at present, 95% of our rivers and 83% of our lakes would fail.
Some conservation bodies have welcomed the promise of new government action. The Royal Society for the Protection of Birds said today that the present ways of judging water purity gave "too rosy a picture" and added:
"There is a lot of work to do to improve the condition of our waters. We hope the Government will now use a wider range of indicators, including nutrient levels in rivers and the condition of wetland wildlife, to show the state of our rivers, lakes and coasts."