Relining 2.6km of Victorian Water Mains at Finsbury Park

In North London, Cullen Utilities is assisting in the relining of 2.6km 36 inch diameter mains on behalf of Morrison's and Thames Water, at a cost of 21 million pounds. The pipes date from between 1850 and 1870 and are at the end of their working life. Once the job is finished, this stretch of main won't need touching again for two generations.

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A Main at the End of Its Life

These are Victorian cast iron mains, some of the oldest infrastructure still carrying water under London's streets. Age catches up with pipework eventually, and this section had reached the point where relining, rather than waiting for failures, was the right call.

How the Relining Works

A trench pit goes in at one end and a launch pit at the other. The new pipe is inserted from the launch site through the existing main to the reception pit, fed all the way through the old Victorian cast iron shell. We're putting in the biggest possible pipe we can within the old main, squeezing the new pipe down to fit and installing it inside the pipe it's replacing. That gives the main a fresh lease of life, somewhere between 50 and 70 years.

Why Relining Instead of Open Cut

Relining has a lot less impact than an open cut replacement would. Customers see less disruption, and road users see far less impact too, since the streets above stay largely untouched compared with what a traditional dig and replace job would mean.

Part of a Bigger Mission

This project sits inside Thames Water's wider push to halve leakage by 2050, which relies on a lot more than relining old mains. Over 95 percent of leakage is hidden underground, so finding it takes real effort. As part of the current investment period, 112km of pipes are being upgraded across London. Smart metering plays a big part too, helping tell the difference between leakage and genuine usage; over a million smart meters are already rolled out, with a further 78,000 planned this year. Jobs like this one at Finsbury Park are what keep the taps flowing, for this generation and the next.