The issue

Sutton & East Surrey (SES) Water, a UK water supply company, aims to reduce water leakage by 24% by 2030. It supplies 160 million litres per day of potable water to approximately 745,000 people, serving the areas of East Surrey, West Sussex, West Kent, and South London. It operates 31 service reservoirs, 23 pump stations, and 8 treatment works covering 835 square kilometres. Covering a vast area with 3,400 kilometres of drinking water mains and serves over 300,000 homes and businesses, leak detection is a challenging task for SES Water.

To tackle this issue, SES Water turned to SUEZ and technology partner ASTERRA to employ the cutting-edge and proven satellite leak detection technology

The solution

Using Synthetic Aperture Radar (SAR), a remote sensing technology that uses radar signals to create high-resolution images of the Earth's surface, ASTERRA was able to identify likely leak locations. The satellite data was overlaid with the pipe network Geographic Information System (GIS), highlighting sections with potential leaks. Points of Interest (POIs) were identified and verified in the field by SUEZ leakage technicians using advanced acoustic technologies. These POIs represent 3% of the company area network and 10% of the analysed network.

The result

From over 1,000 km of pipes analysed, 211 likely leak locations were identified. A total of 219 leaks were confirmed through 59 days of field inspection. This equated to 3.7 leaks per crew day and 2.2 leaks per kilometre inspected. The inspection team reported 171 leaks and customers reported 44 leaks. A breakdown of the leak subtypes is shown in the table below:






 Work order  Other


121 29 44 4


Notably, 94% of the leaks found were non-surfacing, highlighting the effectiveness of satellite leak detection in identifying concealed leaks.

SES Water reported a volumetric saving of 0.9 megalitres per day and identification of 1.1 leaks per POI, which helped the company achieve their 15% leakage reduction target through this AMP period.

Overall, the satellite leak detection project provided significant value by enabling SES Water to identify and address leaks efficiently, contributing to their efforts in reducing water wastage and improve operational efficiency. In the long run, these improvements will help reduce costs and leakage breakout by identifying leaks before they cause major issues.

> 1000
of pipes analysed, identifying 211 leak locations



confirmed during 59 days of field inspection


sub-surface leaks found