The aquifer storage and recovery (ASR) scheme will see drinking water from the mains pipe stored below ground and brought up to the surface when it is needed during the dry summer months.
The water will not have to go through a complex treatment process as it does not mix with the natural, poorer quality groundwater in the aquifer.
This is not the first time ASR techniques have been trialled. In November last year, Southern Water drafted plans for a similar pilot project to store water in an aquifer in Worthing. However, Thames water says this will be the most advanced scheme in the UK.
Thames Water groundwater resources manager Mike Jones said aquifer storage is a “great start” to helping “combat the effects of climate change”.
Aquifers already provide 30 per cent of London’s tap water and the chalk aquifer at Horton Kirby is used to supply parts of Kent.
ASR is used in desert regions across the world and Thames Water groundwater experts began investigating the technique more than 10 years ago. The team identified the Lower Greensand aquifer as a suitable candidate and, in September last year, began drilling a new borehole at Horton Kirby.
When work finished in January, the drill had reached a depth of 250 metres and entered the Lower Greensand aquifer, which already contains groundwater which is unable to be used because it is low quality.
However, by repeatedly putting water into the aquifer, allowing it to rest then recovering it by pumping it back out, the aquifer is cleaned and higher quality water is stored.