WEST Dorset's MP is challenging water companies over the use of emergency storm overflows after concerns were raised about raw sewage being emptied into rivers and the sea.

MP Chris Loder is calling for further investigations over "frequent discharges" from combined sewer overflows (CSOs) on the west Dorset coast. CSOs are used to expel the contents of sewers during periods of heavy rainfall due to the network being unable to cope.

It comes as the Government announced a major Environment Agency/OFWAT investigation after some water companies in the UK were found to have been in breach of their permits.

Mr Loder said: “Over the last few weeks, I have been pursuing the water companies operating in west Dorset for information on sewage outflows. I have challenged one water company on the high readings for discharges in one particular outflow in Charmouth and an investigation is currently taking place.”

He added that the water companies have given assurances that funds have been made available "to invest wherever is necessary to deal with the issue," and said he will be following the investigation closely.

Wessex Water confirmed that there are three storm overflows in the vicinity of the designated bathing water area at Charmouth - one of which operated twice during this year’s bathing season, which falls between May 15 - September 30.

It discharges one kilometre offshore and releases highly diluted sewage – mainly rainwater – during heavy rainfall to prevent properties from flooding when the sewerage network becomes overwhelmed.

“The bathing water at Charmouth is rated Excellent by the Environment Agency, and overflows in this area are used infrequently," a Wessex Water spokesman added.

"When they are used it is mainly during winter months when intense storms can overwhelm the sewerage network, so they operate to protect properties from flooding."

It comes after the Government voted against an amendment to the Environment Bill that would have legally required water companies to upgrade sewer networks.

Instead a vote was passed to require companies 'to secure a progressive reduction in the adverse impact of discharges from storm overflows... reducing adverse impacts on the environment, and reducing adverse impacts on public health.”

Wessex Water's spokesman added: “In an ideal world we wouldn’t have storm overflows, and we support ambitions to eliminate any negative impact that they could have, but this will only be possible when Government legislation prevents housing developers and property owners connecting surface water to combined sewers, which is increasing the frequency of overflow operations.”