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Castle Water has secured a £130,000 refund and ongoing cost reductions for Jockey Club Racecourses after uncovering a significant error in the sewerage charges applied to one of its flagship venues by Thames Water, the network owner.
Jockey Club Racecourses is the largest racecourse group in Britain, operating 15 venues, including Aintree, Cheltenham, Epsom Downs and Newmarket.
The problem related to the Return to Sewer (RTS) allowance applied to the racecourse venue in question, a figure which represents the proportion of water consumed at a property that re-enters the public sewer network. For most commercial properties, network owners apply a near-total default figure. However, where large volumes of water are used for activities that never return to the sewer, such as the irrigation and course preparation carried out at a racecourse, that default assumption is incorrect, and customers can end up paying for sewerage disposal on water that was never disposed of into the sewer.
Through a proactive review of billing data, Castle Water identified that the site’s RTS allowance had been set at 95% by Thames Water. Given the site’s operational profile, the correct figure was 0%. Castle Water challenged Thames Water’s position, worked through the investigation process, and secured a retrospective reassessment covering three and a half years from April 2022 to June 2025. The result was a £130,000 refund for Jockey Club Racecourses and a material reduction in ongoing sewerage charges.
Mary Reynolds, Commercial Director, Castle Water, said:
“This is exactly the kind of case that illustrates why Castle Water’s independence as a water retailer matters along with our extensive experience and willingness to challenge incorrect charges. Castle Water raises more trading disputes than any other retailer in the market. In this case, we identified the error, challenged the network owners’ assumption, and recovered £130,000 for the customer.”
Jockey Club Racecourses is among a range of high-consumption customers for which Castle Water provides specialist billing analysis and wholesaler dispute support. For large sites with complex water usage profiles, in hospitality, manufacturing, agriculture, the public sector and multi-site estates, the difference between a proactive retailer and a passive one can run to six figures.