Water mains flushing

Flushing our network of pipes.

So that you can enjoy the best water possible, and to keep our networks in top condition, we often carry out something called ‘flushing’ as part of our ongoing maintenance work.

What is flushing?

Over time, iron and historic mineral sediment can build up in our supply pipes. If left alone these sediments are harmless and do not cause any problems. However, if they’re disturbed, due to a burst main or when the emergency services use a hydrant, the sediments can be displaced, which may cause tap water to be discoloured, although normally this only lasts for a short period. In order to reduce the impact of disturbances of our network we carry out something called flushing to proactively reduce the risk of this happening.

When we are flushing, we always try to minimise disruption to customers, whilst working as quickly as we can to complete the work safely. The process means you might see water running overground, near to where we are working. Rest assured, we never unnecessarily waste water, and ‘flushing’ only lasts for as long as necessary.

What does flushing involve?

Flushing involves opening a local fire hydrant in a controlled way to increase the flow of water through the pipes.

Flushing the water mains is an effective way of removing the iron and mineral sediment to prevent it causing discolouration. Flushing helps to keep our network in tip-top condition allowing us to provide high quality water 24/7.

Engineers carry out water mains flushing for Bristol Water

Our Network Modelling team will produce flushing plans for each of our supply areas. These plans detail which hydrants to open in which order, for how long and the volume of water to flush. This ensures that only the minimum amount of water is used during the flushing.

Next our Flushing team will visit the area to check that the valves and fire hydrants are accessible and operate correctly.

Where are we flushing?

When and where we are carrying out flushing.

You can check our flushing updates to find out where we plan to do flushing next. You can also check our map for the exact locations covered, and to sign up for notifications of any work in your area.

Flushing updates

A Bristol Water employee holds up a sample of clear water following flushing

Make a claim for flushing

If you're on a water meter, and we’ve told you to run your taps to clear discoloured water, you can claim for an allowance off your next bill.

Claim your flushing allowance

Answering your questions about flushing

How will you let me know of flushing in my area?

Letting you know about flushing

We will send you a text message before we start flushing in your area.

Could flushing affect my water pressure?

Flushing and water pressure

During the flushing work you may experience a temporary reduction in water pressure. Occasionally you may experience a temporary loss of water supply but it will be restored as soon as the work is completed.

This is why we always send a text message to customers in advance informing when we will be flushing in the area. There is no need to contact us if you know that we are flushing in your area, and you have temporary low pressure or a loss of water.

Please ensure we have your correct contact details so that you will receive the text message. If you need to update your details, you can contact us.

Could flushing affect the colour of my water?

Colour of water

You may notice your tap water is cloudy or discoloured, this will only be for a very short period, until we move to the next fire hydrant. Your water could also look brown, or you might see bits in your water. Don’t worry though, the discolouration is harmless.

If this happens, try not to drink straight from the tap and avoid using the dishwasher or washing machine until the flushing is completed. If you have a combi boiler or electric shower to heat water it is best not to use these during the flushing.

You can test to see if the pipes have cleared by letting your tap run for a few minutes.

Letting you know about flushing

We will send you a text message before we start flushing in your area.