The cold weather significantly increases the likelihood of leaking water and gas mains, which quickly go on to become bursts. Low ground temperatures cause dramatic contraction in old cast iron mains and this causes cracking and splitting particularly at seams and valve locations.
Both Thames Water and Southern Gas Networks have prepared for a large increase in volume of urgent works to repair these leaks as quickly as possible. Gas leaks can be smelt as gas seeps out of the ground or from utility apparatus such as telecoms boxes. Many water leaks are ‘visible’ because water will be seen running out of the ground or around apparatus in the street. However there are equally many ‘hidden leaks’ where it is not immediately apparent; these can cause considerable damage to the subsurface layers if left for long periods of time and will also eventually become much larger visible bursts. Both companies are increasing the number of pro-active teams that go out and search for leaks before they become visible or problematic – they have been doing this since autumn to catch small leaks.
The following free phone numbers should be used to report leaks:
WATER: 0800 714614
GAS: 0800 111999
Please do not assume that someone else has phoned it in. Please do not report these to the Council.
Repairs to leaking mains can cause considerable problems and often require periods of time where holes are left open while specialist equipment is built to repair the leaks. Additionally in cold weather materials used to reinstate excavations, particularly concrete, do not set correctly. For gas leaks, a common action to mitigate immediate danger is to ‘vent’ nearby utility boxes – this involves lifting the lids of boxes to allow gas to escape from ducts and pipes. These can be left open for many weeks and be some considerable distance from where the escape is. However these are not forgotten – SGN will attend the area several times a week and take gas readings to ascertain levels of gas in the area. If this reaches dangerous levels then works will begin to excavate and repair the leak. All companies involved have to prioritise works across our borough as well as other boroughs in south London. The On Street Services team actively monitors works on the public highway and works closely with utility companies to minimise disruption as much as possible.
With the start of another icy blast of cold weather the council’s Roadworks Bulletin this week contained a useful bit of information about water and gas leaks (which I’m posting as much for my own information):