A stretch of river that runs through the town was granted bathing status in 2021, but last year the Environment Agency said swimming is “not advised”, as the water quality is poor because it contains effluent from storm overflows and runoff from livestock farms.

Yorkshire Water is installing another 120 sewer level and flow monitors in the town, but also trialling 21 new water quality monitors along the river over 12 months.

The company wants to find out if they can accurately measure levels of ammonia, as well as the temperature, pH values and turbidity.

A swimmer jumps into the River Wharfe in Ilkley

It comes after the Government announced water companies will be legally required to actively monitor bathing waters from 2025 and take action when the water quality is poor.

Thomas Ogden, a waste networks specialist at Yorkshire Water, said the trial “will further our understanding of the sewer network” as the company looks to reduce the number of discharges.

“The existing smart network project, combined with the 21 water quality monitors we are trialling will allow us to link the data, analyse it quickly and enable us to provide real time information to people looking to enjoy the bathing water in Ilkley,” he said.

“Longer term, we hope to be able to forecast what we expect the river water quality to be many hours ahead of expected bad weather to help inform people if it is a suitable time to swim or not.”

Yorkshire Water is also installing a new sewer that will significantly reduce the amount of waste that is pumped into the River Wharfe in Ilkley following periods of heavy rain, when it opens in January.

According to the company, it will reduce the frequency of discharges from Rivadale Storm Overflow by 40 per cent and halve the volume of wastewater discharged during those events.

On the BBC documentary Paul Whitehouse: Our Troubled Rivers, which aired last month, it was revealed that combined sewer overflows were used to discharge sewage into the River Wharfe and its tributaries for more than 13,000 hours in 2021.

During the documentary, water quality campaigner Mark Barrow pulled a clump of wet wipes and sanitary towels out of the river in Ilkley, before he showed footage of pieces of human waste floating in the water.

Figures released by the Environment Agency show the overall number of discharges recorded by Yorkshire Water dropped by 22 per cent, from 70,062 to 54,273, between 2021 and 2022.

According to the data, the amount of time sewage was allowed to spill into Yorkshire’s waterways fell by 43 per cent, from 406,131 hours to 232,054 hours.

Chief Executive Nicola Shaw said she was pleased with the reduction but last year’s drought had a significant impact as there is less pressure on the sewage system during spells of dry weather.

New technology could tell people when it is 'suitable' to swim in Ilkley river