Thames Water Cracks Down on Illegal Water Connections

23 Convictions Secured Against Illegal Connections in 2026

Thames Water has stepped up action against unauthorised connections to its water network, securing 23 convictions during the first five months of 2026. The convictions covered 47 separate offences, including cases involving repeat offenders, and resulted in combined fines and legal costs of £89,788.

The action forms part of Thames Water's ongoing efforts to protect its clean water network, reduce unnecessary water loss and ensure that connections to the network are carried out correctly and legally.

What Is an Illegal Water Connection?

An illegal or unauthorised connection can occur when a property, development or business connects to the water network without the necessary approval or inspection.

Examples can include:

Unauthorised connections can put the integrity of the water network at risk and may result in significant quantities of treated drinking water being lost.

Enforcement Across London and the Thames Valley

Among the cases highlighted by Thames Water during 2026 was a plant hire company prosecuted for repeated offences involving unauthorised connections. Another case involved the former owners of a Southwark property that had been converted into three flats, resulting in combined fines of more than £15,000. A servicing company was also prosecuted following the unauthorised use of a standpipe in Abingdon. These cases demonstrate the importance of making sure that water connections, temporary supplies and standpipe use are properly authorised before work begins.

Protecting the Water Network

Thames Water says tackling illegal connections helps protect both the quality and security of the water supply. Unauthorised connections can also lead to the loss of large quantities of treated water and reduce revenue that could otherwise be invested in maintaining and upgrading water infrastructure.

Developers, contractors and property owners should therefore make sure the necessary permissions and inspections are in place before connecting to the public water network.

Reporting an Illegal Connection

Anyone who suspects an illegal water connection or the unauthorised use of a standpipe should report it directly to Thames Water so that it can be investigated.

Need Professional Drainage Support?

Pinpoint Drainage Services provides professional drainage solutions for commercial, industrial and domestic properties, including drain surveys, drainage mapping, drain cleaning, repairs and maintenance.

If you require advice or assistance with your drainage system, contact the Pinpoint Drainage Services team.