Four new swimming spots will be monitored to ensure the lake has good quality water for bathing.
The Derwentwater and Coniston sites in the Lake District have recently achieved bathing water status. This means water quality is monitored weekly from May to September.
The Environment Agency said this information would help hold water companies accountable.
The comments come against the backdrop of continued criticism of the water quality of Lake Windermere, one of the Lake District's most famous lakes.
Locations to be monitored are those recently designated for bathing, namely Derwent Water, Crow Park, Keswick, Coniston Boat Center, Coniston Brownhow and Monk Coniston, Coniston Water.
Andy Brown, from the Environment Agency, said: “Our specialist samplers now come in every week during the swimming season.”
Sample information will be published on Swimfo's website where people can check the water quality.
sewage spill
This week it was revealed that a United Utilities system failure caused sewage to spill into Windermere for 10 hours in February.
Some activists accused the Environment Agency of incompetence, a charge the agency strongly denied.
“From the day we got the report, we got there very quickly. We took samples and started an investigation,” Brown said.
“This is ongoing and if we find that there has been a violation of that release, we will take the strongest possible action under the law.”
Mr Brown said Windermere's water quality has been rated as “excellent” since 2014.
Nigel Wilkinson, from Lake Windermere Cruises, said he hoped the monitoring would make a difference for people visiting the lake to enjoy water activities.
“Having quality bathing water is important, but communicating our high standards is also very important,” he said.
Test limitations
Ben Surridge, a biogeochemist at Lancaster University, warned that the test had limitations.
“Currently, the water is only operational between May and September each year, with people using the water for recreation at other times of the year and in other parts of Windermere,” he said.
“Therefore, at this time, there is clean water in Windermere in terms of bathing water conditions that are monitored using standards.”
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