Scottish Water Mains Flushing

RPS has been working with Scottish Water since 2014 to understand and improve water quality within their water infrastructure network through a programme of mains flushing.

Key Details

Project name
Mains Flushing

Scottish Water




Services provided
Mains conditioning (PODDS) and flushing


Over time, natural sediments can build up in water mains pipes which could affect the taste, clarity and colour of water.

This project required a number of investigations to obtain water quality and pipe condition information followed by the subsequent identification and design of various complex solutions for delivery by contractors.

flushing image 2.jpg


The project originally focused on traditional mains rehabilitation solutions such as replacement, PU lining and swabbing but significant opportunities were identified to utilise alternative mains cleaning techniques such as mains conditioning (PODDS) and flushing. These have considerably lower costs and have been delivered quicker, providing benefits to customers earlier.

For Scottish Water we typically undertake unidirectional flushing as the preferred method of flushing the water mains of a water distribution system. This is accomplished by closing specified valves and by flushing strategically located hydrants. By closing specified valves, the velocity of water through the mains is controlled to the minimum re-suspension velocity. It is generally considered to be more effective at removing sediments than conventional flushing and also uses less water. The sequence of the flushing design will enable clean water to be carried forward into each downstream section.

Each week our teams are flushing almost 50km of distribution main and improving the quality of Scottish Water’s customer’s potable water.

Since we began the project almost 4000km of main has been flushed by our field teams.

Get in touch

Your contact information:

All fields are mandatory *

Get in touch

Your contact information:

All fields are mandatory *