Serving parts of North West London and the Home Counties.

Cleaning our water mains

Why do we need to clean the water mains?

The water we provide you is of a very high quality. However, over time, natural sediments may build up in our pipe work. If these are left, you could occasionally experience some discolouration of your water. As part of our routine maintenance programme, we carry out regular activity to flush the water mains to remove these sediments, where this is required.


About our works

We are principally employing a technique called Ice pigging to clean the majority of the trunk main network. Trunk mains supply water from our water treatment works and storage facilities such as our towers and reservoirs, into the local distribution network. Local distribution mains, those pipes that supply water from trunk mains to customer’s homes, will be cleaned by means of a systematic flushing programme.

To understand more about how we clean the water by ice pigging or mains flushing click here.


Where we are working


Denham Village: 18– 28 April


We will be carrying out mains flushing in Denham Village.

Please see below for a list of streets where we will be working.


Please see below for a list of streets where we will be working.

Ashmead Drive, Ashmead Lane, Baconsmead, Blacksmiths Lane, Bronsdon Way, Campion Close, Cheapside Lane, Courtfield Gardens, Denham Avenue, Denham Close, Denham Way, Field Road, Ford End, Hollybush Lane, Lindsey Road, Mead Close, Mount Lane, Old Mill Road, Oxford Gardens, Oxford Road, Priory Close, Ronan Way, Southlands Road, The Pyghtle, Village Road, Wenlack Close, Wolstan Close


Our working hours are from 22:00 – 06:00 on the following dates:

  • Tues 18 April

  • Wednesday 19 April

  • Thursday 20 April

  • Friday 21 April

  • Monday 24 April

  • Tuesday 25 April

  • Wednesday 26 April

  • Thursday 27 April

  • Friday 28 April


South Harefield: 2– 8 May

We will be carrying out mains flushing in South Harefield.

Please see below for a list of streets where we will be working.


Broadwater Gardens, Broadwater Lane, Church Hill, Church Road, Gore Close, Harvil Road, Hinkley Close, Moorhall Road, Peerless Drive, Priory Avenue, Priory Close, Priory Gardens, Sedley Grove, St. Annes Road, St. Marys Close, St. Marys Road, Truesdale Drive


Our working hours are from 22:00 – 06:00 on the following dates:


  • Tue 2 May

  • Tue 2 May

  • Wed 3 May

  • Thu 4 May

  • Fri 5 May

  • Mon 8 May



Find out how our works may affect you

  • Your water may be interrupted between 10.00pm and 6.00am

  • Your water may become discoloured or cloudy. Discoloured water is not harmful to health. You should run the first mains-fed tap in your house at a normal rate for up to 30 minutes. Metered customers who experience discoloured water as a result of this work should ring our customer centre on 0800 521 660, as you may be given an allowance on your bill.

  • You may experience lower water pressure

  • You may notice there is a change in taste or odour after the work is completed, this will almost certainly be associated with the mains flushing process


To find out if there is any planned work being carried out in your area, please click here to search our Customer Zone.








Let us know your feedback

Fields marked with * are mandatory.

    How easy was it for you to find and/or understand the information on this page today?


    Comments *

    This box is for feedback only. If you have any queries about your account or water please contact us.

    Please do not use this space to note any account details or requests.

    If you would like a response please enter your name and address below