SOUTHERN Water's infrastructure has been branded inadequate by regulators, as Isle of Wight surfers complain beaches 'reek of sewage' leave them 'nauseous and dizzy.'

In the past 30 days there have been 15 instances of increased risk of water pollution due to heavy rain on the Island — in Shanklin, St Helens, Seagrove, Ryde, Cowes and Gurnard — according to the Environment Agency.

Heavy rain can lead to wastewater entering the sea, as more water arrives in sewers than can be processed.

Excess water is stored in large tanks, but when these fill up wastewater is filtered and released.

The wastewater is often from washing machines, showers and dishwashers, diluted by rain and run-off water from roads and land.

Matt Harwood, the Isle of Wight regional rep for Surfer's Against Sewage, said Southern Water must do more.

He said: "As soon as we get heavy rainfall, water is discharged. A lot of it gets treated but what they haven't got at the moment is the facilities to deal with the amount of water.

"We have got an increase in population and more surface run-off. They are not putting the infrastructure in place to deal with the increase in water run off."

Ofwat, the water services regulation authority, said Southern Water's standards fell below those of other sewerage companies in a report published in June.

It said storm tanks were too small, equipment was not properly maintained and there was a lack of capital investment.

Southern Water said it has invested millions in its wastewater network in recent years, including a £4 million project in Shanklin which includes installing a new storm tank.

Ofwat will soon release its final decision on what action will be taken against Southern Water for 'significant breaches of its licence conditions and its statutory duties.'

A criminal investigation by the Environment Agency into the environmental aspect of Southern Water's alleged breaches, which was launched in March, 2016, remains ongoing.

The Isle of Wight Council said bathing waters on the Island had 'never been cleaner' and has launched a new campaign to keep them that way, working with Southern Water and the Environment Agency.

The campaign has encouraged recycling, binning litter and dog mess, and not flushing wet wipes, cotton buds or grease down drains.

It also suggested following the 'if it’s yellow, let it mellow; if it’s brown, flush it down' rule.

Matt praised the council for the campaign, but said more needed to be done to challenge Southern Water.

He said: "I think it's really good that the council sees this as an important issue, but where is the challenging of Southern Water?

"We all pay and the two things we expect from our water company is clean water through the taps, and knowing dirty water is disposed of properly.

"Unless you have very, very extreme weather, this should not be happening."

The council said challenging Southern Water was the responsibility of its regulators, and the council's campaign was about doing simple, everyday things to keep the coastline clean.