99.95% compliance with drinking water standards achieved in 2024
Guernsey Water’s 2024 water quality report has been released, marking another strong year of compliance against 6,000 analyses.
During 2024, the utility provided 4,395 million litres of safe drinking water, transferred via 420km of water main and on to islander’s taps, toilets, showers and appliances.
Daffyd Griffiths, Water Quality Risk Manager at Guernsey Water, said: “Our robust sampling regime is able to continue demonstrating Guernsey Water’s high levels of compliance against UK water quality regulations, which we follow as best practice.
Of the 6,000 + analyses, three breaches occurred, one from Juas water treatment works, where resamples were returned clear, and two, from a single sample, taken the West Tank at Forest Road Treated Service Reservoir. This sample failure prompted the precautionary removal of the tank from supply for investigations to take place.
Work to upgrade the West Tank at Forest Road was scheduled to take place in future years, but was brought forward following the compliance failure, this work was completed in 2025 using local contractors and put back into service as quickly and safely as possible.
The utility advised that investing in aging infrastructure and preparing for population growth on the island was vital in ensuring the continued quality of the island’s water.
In addition to a case study on the Forest Road West Tank, the report highlights the value of the recent refurbishment of St Saviour’s Water Treatment Works (WTW) which has further improved water quality, with the introduction of UV disinfection, and improved resilience. The works now operates in line with treatment processes at Juas WTW, allowing Guernsey Water’s production team to carry out much of the refurbishment themselves thanks to the experience and knowledge gained from the management of Juas WTW.
“Ongoing investments such as these are critical to ensure we can continue to provide high quality drinking water for years to come.” said Mr Griffiths.
Pollutants such as pesticides are featured within the report, which states that water from the Vale Pond catchment was still unable to be collected reliably due to pesticide contamination.
“Although our results show a drop in the levels of glyphosate in un-treated water over recent years, an increase was seen in 2024. Samples were collected following the first rainfall after a fair-weather bank holiday weekend, and the results strongly suggest that this spike was a result of applications being made ahead of wet weather. A reminder to use pesticides responsibly, and to avoid spraying ahead of any forecast rain” said Mr Griffiths.
Guernsey Water’s 2024 water quality report can be viewed on water.gg/waterquality.