Thames Water is continuing to crack down on illegal network connections - the UK’s largest water company has secured 23 convictions in the first five months of 2026 against companies and individuals who have illegally connected to its network.

The convictions relate to 47 separate offences several of which were committed by repeat offenders. The 47 offences have resulted in total payable fines and legal costs of £89,788.

Thames Water said illegal connections to the network compromise the security and quality of drinking water as well as the loss of millions of litres of water. It also results in a loss of vital revenue.

Unauthorised connections include:

developers linking a property to a water main without approval or inspection

unauthorised use of existing connections, such as splitting one supply across multiple flats

illegally abstracting water by tapping into a pipe or standpipe without permission or metering, to avoid paying for water usage.

Key prosecutions so far this year include:

McFen Plant Hire Ltd convicted a fourth time, in total 10 offences, this time in Canning Town, London, fined nearly £4,000

Dinah Adjei-Barwuah and Barfour Adjei-Barwuah: prosecution against two former owners of a house in Southwark that was converted into three flats. Total fines reached £15,280.

Hudmac Servicing Limited: unauthorised use of a standpipe in Abingdon resulting in a fine of £2,047.

Claire Rumens, Thames Water’s illegal connections manager, said:

“Our efforts to identify and stop illegal connections are crucial to protecting the integrity of our network. This crucial work prevents millions of litres of water from being wasted and helps us meet our statutory duty to safeguard the supply.

“As we ask customers to use water responsibly and deploy teams around the clock to fix leaks, we’re equally committed to tackling unlawful use of our system. We will always try to work constructively with individuals and businesses to educate them and reduce the risk of repeat offences.”

Thames Water has the right to prosecute all offences but may offer a one-off retrospective charge for a non-aggravated standpipe first offence.

Standpipes can be hired from Thames Water’s authorised service provider.