Thames Water released sewage into Farnham Park for the equivalent of 21 days in 2024.

The 505 hours of untreated or diluted sewage discharged into the park's waterways amounts to 5 percent of the entire year, according to data from Sewage Map UK.

The data, collected through Event Duration Monitoring (EDM) by Thames Water, provides real-time updates on storm overflows, which release untreated or partially treated wastewater into the environment during heavy rainfall.

This marks an increase of nearly 200 hours compared to the previous year, based on figures from the Department for Environment, Food & Rural Affairs (Defra).

In August, Thames Water faced the threat of a £104 million fine from the water regulator Ofwat after failing to ensure that storm overflows, which discharge untreated wastewater, occur only in exceptional circumstances.

A Thames Water spokesperson said: “We know how much people enjoy and appreciate rivers, and we are committed to seeing waterways thrive, but we can’t do it alone.

“Farming, industry, road runoff, wildlife and increasingly extreme weather also play a role in river health.

“We have clear and deliverable plans to upgrade 250 of our sites across the region, to increase treatment capacity and reduce the number of storm discharges including at our site in Farnham.

“As infrastructure ages and demand on it increases, more investment is needed across the entire sector. Last year our region experienced one of the wettest winters since records began.

“This alongside more monitors across our region can reflect the higher figures in data. We’ve put transparency at the heart of what we do, and we were the first water company to publish a real time data map on our website, which in its first year was viewed over 350,000 times.”