Report by Hannah McNulty.
Matt Staniek began his campaigning for better water quality in Windermere after finding pollution in the place he has swam in since he was a boy.
He has left his job and is living off savings in order to continue his work.
After getting more than 100,000 people to sign a petition supporting him he's now been promised a meeting with the authorities involved.
Algae in water shows chemicals like phosphate are present and they damage the ecosystem - it's coming from raw sewage from a plant in Ambleside but also privately owned septic tanks and agricultre.
Some overflows are allowed during heavy rain to prevent flooding but its the frequency - and not just here - that has led to urgent calls to act now
Water authorities though have said there is no quick fit.
United Utilities say its aready spent millions and is working with the Environment Agency to limit the amount of phosphate entering Windermere
The firm has pointed out that combined sewer overflows are mostly rainwater, containing small amounts of wastewater. This is a feature of sewer design to stop them backing up in heavy rain and causing flooding to homes and roads.
The company has pointed out that there are two sewer overflows on Windermere, which contribute five per cent of the phosphate entering Windermere. NMost of the rest comes from private septic tanks and agriculture.
It also encouraged people to pick environmentally-friendly products which will enter the water, such as washing-up liquid.
The Environment Agency has announced it's investigating the issue across the country including other places in Cumbria
The Lake District National Park Authority also commented on the issue.