BT’s water journey

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Recognising that the connections it makes have the potential to solve the world’s biggest challenges, the Group’s purpose is to create positive change by connecting people for good. It has an ambition to be a climate-resilient, net zero business by 2031.

With a large, complex property portfolio, BT partnered with Waterscan to improve its water management processes, enabling BT to:

  • Become the largest Self-Supply licence holder, switching over 6,750 supply points.
  • Outperform comparable water retailers with a market performance score over 99%.
  • Cut the administrative burden of processing 12,000 invoices annually to less than 50.
  • Detect leaks wasting 0.5 billion litres of water.
  • Save over £3 million in water spend.
  • Identify and correct compliance issues for around 100 gap sites.
  • Positively influence how the water market develops for non-household customers.
BT's Water Journey Timeline - 2017-2023. Self-Supply. Waterscan.


BT Group has a large and diverse property portfolio, with significant variability in water use across its 6,000 UK sites, which encompass telephone exchanges, warehouses, offices, data centres and high street retail stores. As well as staff welfare facilities, the company has cooling systems installed at many sites that rely on mains water to operate effectively.

In 2018, some 25% of BT’s water meters had not been read for a year or more (referred to as long unread). The resulting lack of data impeded the company’s ability to analyse consumption and set targets, control water leaks and manage budgets with certainty. Additionally, the sheer size of the BT estate created some 12,000 paper water bills to process, draining internal administrative resources.

Market deregulation gave BT an opportunity to make significant changes to the way it procured and managed its water supply and water waste. After analysing all options across the water market, BT chose to Self-Supply in partnership with Waterscan. The primary aims were to gain visibility of its water use, reduce cumbersome administration and implement consumption controls.


Since securing its licence from Ofwat, BT has switched over 3,400 meters and 3,600 sites to Self-Supply, including EE stores, in an ambitious and staged programme. The scale of this transition made BT the largest Self-Supply retailer in the water market, comparable to a traditional large water retailer. 

Waterscan located and verified almost all of BT’s long-unread meters, reducing this proportion from 25% to under 1% of its meters. Further, Waterscan identified nearly 100 gap sites (those receiving mains supply but without charge), ensuring transparency and compliance for BT across its estate.

The monumental shift in BT’s visibility of its water use has enabled it to identify and mitigate previously hidden commercial risks and make informed budgetary decisions.


With a schedule of frequent, accurate meter reads, Waterscan enabled BT to take control of its water spend, administration and wastage.

Since switching to Self-Supply, BT has saved £3 million on its water spend, and has been cushioned from inflationary impacts through paying wholesale water rates over default retail rates: in 2023/4, BT will save £400,000 in this way. Further savings have been achieved by reducing the administrative time needed to validate and process paper water bills from multiple suppliers.

Data analysis also identified several large underground leaks on the BT estate. Repairing these has saved over 0.5 billion litres of water, while new benchmarks are enabling effective leakage controls for the future.

“As water availability trends towards more stress, and greater transparency around reporting and disclosure come into play, water is fast becoming a priority. Self-Supply has been a great foundation for unlocking opportunities to boost our climate resilience.”

Matthew Power, Utilities Commercial Specialist – BT Group


BT has demonstrated leadership on water via its attendance at the Self-Supply Users Forum which offers quarterly knowledge-sharing with other licence holders and key bodies shaping the UK’s water landscape including Ofwat, MOSL, Defra, and the Environment Agency. BT also co-hosted a peer group event in 2020 to share BT’s experience of the water market.  

One of the few global companies rated A for disclosure on climate change via CDP, BT also encourages supplier action and accountability. In recognition of its supplier engagement, BT is listed on CDP’s Supplier Engagement Leader board.

“We now have incredible insight into the challenges around water, and how these could impact our own operations and those of our supply chain.”

Matthew Power, Utilities Commercial Specialist – BT Group

Moving forward

Despite the complexity of its estate and significant legacy issues around meter reading, BT embraced the opportunity presented by water market deregulation and has achieved high level savings in consumption, time and money. This experience is enabling BT to influence the future development of the water market and drive responsible water management across its business, with newfound visibility and controls. It is also now in a position to extend its profile by working towards disclosing on water through CDP and TCFD.

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