New figures have revealed the extent of London’s mains water leak problem, with Wandsworth and Westminster being revealed as London’s leakiest boroughs.
Water mains leak detection firm, Aspect, has examined its first-party callout data to determine which of London’s boroughs are the leakiest.
According to the figures, Wandsworth is London’s leakiest borough, followed closely by Westminster and then Lambeth.
The City of London sees the fewest mains water leaks, although it must be noted that the City is the smallest London borough by size. Huge construction work in the City of London probably means many communication pipes and supply pipes have been upgraded.
Barking and Dagenham saw the next fewest leaks, followed by Bexley and Hillingdon.
Murray Kemp, leak detection trade manager at property maintenance experts Aspect, said: “It’s not surprising to see the most mains water supply pipe leaks taking place in central London. A lot of the supply pipes in Wandsworth and Westminster are made of lead and are easily 150 years old. Lead deteriorates over time, leading to pinhole leaks which can quickly grow more numerous, especially if water pressure is increased along the line.
“Wandsworth in particular has seen a large increase in the number of housing blocks over the last few years, all of which need a strong water supply. Water pressure in these areas will have been increased to ensure all new properties have sufficient pressure; this will speed the process of deterioration and will make leaks more noticeable as more water will be lost than if the water pressure was lower.
“From the data, it appears that areas in outer London experience fewer mains water leaks. This is likely because much of the network here is not so old, and therefore has had less time to develop faults. As this network ages, we can expect to see more mains water leaks in these areas too. Freak leaks can occur anywhere, so wherever you live in Greater London, there is always the possibility of a leak occurring on your supply line soon.”
What to do if you think you have a mains water supply leak
If you believe you have a mains water leak, there is a quick and easy way to confirm your suspicions:
1. Turn off your water supply
You can do this by turning your stopcock valve, often found under your kitchen sink. You can check the water is off by turning a tap on and within a few seconds the water will stop.
2. Take a meter reading
Your water meter can often be found on the street outside your property boundary. Once you’ve ensured your water is turned off, take a meter reading.
3. Wait for as long as you can
Next, it’s a waiting game. It’s recommended to wait for a couple of hours or more before taking a second meter reading. If the reading has increased while your supply has been turned off, it indicates a leak on the supply pipe between the meter and the internal stop valve.
A large leak will mean the reading on your meter will increase in a few minutes, whereas a smaller leak could take an hour or more to show on your meter.
4. Call a leak detection expert
Once you’ve determined that you have a leak, it’s time to find out exactly where it is. For this, you’ll need to call a leak detection expert. They can use special equipment, including sensitive acoustic devices to pinpoint the location of a leak in buried pipes without needing to excavate.
If the leak is within your property boundary, you’re responsible for the cost of repairs. If the leak is outside of your boundary, your water provider must repair the leak.
