The Water Industry Commission for Scotland (WICS) has today published its annual assessment of Scottish Water’s performance in 2024-25, highlighting strong service levels and drinking water quality, alongside areas requiring greater focus.
Scottish Water delivered its highest-ever Outcome Performance Measure (OPA) score, improving in eight of nine measures, including reductions in supply interruptions, low-pressure incidents, and serious pollution events.
Customer satisfaction remained high, and developer satisfaction continued to improve. Favourable weather conditions also supported improved service levels.
Average household bills were the second lowest in the UK, rising more slowly that the maximum allowed in the 2021–27 regulatory period.
Scottish Water has broadly maintained its investment programme, with £2.825 billion invested to date.
However, WICS highlights important challenges. Capital investment for the 2021–27 period is now forecast to be around £4.45 billion (in 2017–18 prices) around £400 million below the level assumed in the Final Determination.
This shortfall reflects lower-than-expected revenue from charges and rising costs. If Scottish Water maintains strong financial and operational performance, this shortfall could reduce to around £300 million. WICS will continue to monitor this closely and expects Scottish Water to explain the implications for risk, outcomes and customer benefits.
There has been slippage in delivering some longer-term commitments, including the removal of priority unsatisfactory intermittent wastewater discharges (UIDs) and progress against the Net Zero Routemap milestone for reducing operational emissions.
Leakage levels, household water consumption and discharge permit compliance are higher than the industry average across Great Britain.
As part of our approach for the 2027-33 regulatory period, we are introducing a broader set of performance measures and expect Scottish Water to make further improvements in these areas.
WICS will continue to monitor the delivery of Scottish Water’s investment programme, including progress on sewer overflows, climate change targets, and the Net Zero and Improving Urban Waters Routemaps.
Chief Executive David Satti said: “Scottish Water delivered strong results in 2024-25. Customers continue to receive excellent drinking water quality, high levels of service and among the lowest household bills in the UK.
“But our assessment also highlights where further focus is required. We will continue monitor Scottish Water’s performance closely over the remainder of the regulatory period to ensure that customers receive the outcomes expected.”
[1] In 2025-26 Scottish Water’s average household bill is the lowest in the UK.
