Liberal Democrat Party leader Sir Ed Davey speaks to ITV News West Country
The Liberal Democrats have vowed to clear up the country's rivers if they end up in power.
It comes as the party gathered for its first conference since they won the Somerton and Frome by-election.
The Liberal Democrat is holding its party conference in Bournemouth, with other parties to follow in the coming weeks.
Speaking to ITV News West Country at the conference, leader Sir Ed Davey said his party is "nowhere near at it's peak" and is hoping to make big gains next year.
Speaking on the topic of water pollution, he said: "We need to get much tougher on the water companies, so far the Conservatives have voted to allow the water companies to continue to pump their filthy sewage into our rivers and our seas, that's got to stop.
"We need much tougher action from the regulators, from OFWAT, from the Environment Agency to force the water companies to clean up, they've made billions of pounds of profit."
It comes as water companies have been instructed to pay out £114million to customers by lowering bills due to environmental protection progress being "too slow".
The party wants blue flags to be flown at rivers that are clean, similar to the scheme for beaches.
When asked if this was "just a gimmick" instead of a policy that could make a change, Mr Davey replied: "No, I think lots of people want to know that if their kids are swimming in the river, or the sea, that it's safe for them to do so."
At the Dorset conference, the party axed its plan to increase income tax to fund social care.
Commenting on this decision, Sir Ed said: "We're arguing for free personal care. We're arguing for £5billion so people can leave hospital more quickly, a lot of them can get cared for at home rather than going to care homes."
When asked where this money is going to come from, he replied: "It's what I call a spend-to-save policy.
"We reckon we'll get about £3billion of that back through efficiences in the NHS because you can be discharged more quickly and people won't have to be cared for in care homes."
The party is targeting a number of seats across the region. These include:
Thornbury & Yate
Wells & Mendip Hills
Somerton & Glastonbury