Serving parts of North West London and the Home Counties.

Water main failure on A41

Between Apex Corner and Broadfield Avenue in Edgware

We are committed to providing high quality water to the communities we serve and to do this, we work hard to monitor and maintain our network of pipes and equipment to minimise the number of unplanned events on our network.

We look after over 10,000 miles of water mains – enough to stretch from London to Sydney – and transport 900 million litres of water a day through them, but there are occasions when bursts occur that can affect our customers.

We are continually working to understand the condition of our network and make significant investments to keep these events to minimum. Between 2015 and 2020 we will be spending around £90 million monitoring, inspecting, reinforcing and replacing our network.

On Friday 10 June we experienced a burst of our 21 inch water main on the A41 between Apex Corner and Broadfield Avenue and we regret any inconvenience that was caused to our customers and motorists by this.

During this event we received a number of contacts from our customers and members of the public travelling through the area and we would like to take this opportunity to answer some of the common questions.


Why did this burst happen?

There are many different factors which can cause bursts to happen, such as ground movement caused by seasonal temperature changes, extreme cold weather, high pressures through pipes, traffic vibrations and unavoidable weak points where pipe work is connected to joints and valves.


Did Affinity Water not know that this was going to happen and act on it in advance?

We are continually monitoring our network and working to improve our knowledge of it, but we did not know that this burst was going to happen.


Do pipes usually burst in the morning?

Pipes can burst at any time of the day or night. There could be an increase in pressure at night as a result of reduced demand, and therefore we work hard to control pressures, to maintain a “calm” network wherever we can, in order to minimise this effect


This trunk main has burst before, is it due for replacement?

The results of our tests on the pipe wall material have shown that this main is still in good condition and we have not identified this type of pipe as a significant burst risk, therefore we are not planning to replace it.


Is there more that you could have done to minimise the impacts the burst on customers and motorists?

We had identified that a failure of this main will have a significant impact on our customers and it has been included in our burst mitigation programme. We will be starting works later this year which will allow us to isolate this section of main in the future, without it having a detrimental effect to our ability to supply customers.


Could the repair have been done more quickly?

When a large main bursts which is located on a main road the repair is always challenging. Our repair team responded quickly and worked continuously to isolate the main, locate the burst, repair the pipe, restore supplies and re-open the road.