WATER COMPANIES said this week they faced a £6bn bill to meet new European standards for discharging wastewater into rivers and streams.
And they fear that a forthcoming ban on discharging toxic materials into water courses could cause worse environmental damage in other ways.
The Priority Substances directive lists 33 priority substances, including mercury and lead, that will eventually be banned from being discharged into water courses.
Yorkshire said introducing extra treatment processes would produce 175,000t of carbon dioxide, 400t of nitrous oxide and 900t of sulphur dioxide.
At the NCE sponsored Water Framework Directive conference, Tony Harrington, head of environment, health and safety at Yorkshire Water, said the cost of removing these substances would cost it £880M.
'Across the industry this equates to £6bn, ' he added.
Water companies fear the environmental benefits of removing these substances have not been quantified.
'The cleaning up of one media, only to pollute to a greater extent another, seems to run against the very principals of the Treaty of Rome, under which the European Union works, ' said Harrington.
'Somehow someone has to think of how to apply the polluter pays principle and more effort has to be focused on this, ' said industry body Water UK policy advisor Steve Entifo.
Information produced by Yorkshire Water and UK Water Industry Research has been presented to the Department for the Environment, Food & Rural Affairs, MEP's and European water body EUREAU.
These organisations sit on the advisory forum for priority substances, and are consulting on the new directive.