THAMES WATER engineers are analysing samples from a 70 year old cast iron water main to establish the cause of a major burst in central London last week.
Water poured into dozens of basements in the Russell Square area and a road had to be closed to traffic for a week for repairs. Insurance assessors are estimating damage costs.
The burst happened about 6.30am last Friday but it took four hours to turn off the water as Thames had to close nine separate valves on the 760mm diameter main.
Their condition meant two of the trunk valves needed up to eight men to shut them.
'A whole series of factors could have been responsible (for the burst), from temperature changes to tree growth or traffic loadings,' a Thames spokesman said.
He said it was not possible to draw parallels with the huge burst main in north London last year.