Choosing the best way to replace our pipes is key to making sure we complete the project at the agreed cost and keep disruption to a minimum.

We go through several stages of planning to work out the best way of replacing the pipes in a particular area:

• We carry out a full street-by-street survey.
• We dig trial holes and take pipe samples to look at the ground conditions and to find out if other utilities' pipes and cables are running through the area.
• We work closely with partner agencies such as the highways authorities and other utilities, to make sure any disruption is kept to a minimum.

How it's done

Directional drilling

Sometimes it may be more appropriate to use directional drilling rather than having to dig a trench to replace the pipe, or inserting a new pipe.

This involves drilling a pilot tunnel with a precision-guided drill, then pulling the new pipe back through the tunnel.

Pipe bursting

Most mains replacement work is done underground, with only two small holes dug at each end of the section of pipe that is being replaced.

We push a steel rod into the old water main and then use the rod to pull a cutting tool back through the pipe.

This breaks up the old pipe and at the same time we pull a new pipe into the space left by the old pipe.

Inserting new pipes

Wherever possible, new plastic pipes are placed inside the old metal ones.

Although the new plastic pipes are smaller, the smoother surface means the amount of water carried through the pipe is not reduced.

Replacing old pipes

If we cannot insert a new plastic pipe, we will dig a new trench and replace the old pipe completely with a new plastic one.