The huge “supersewer” that will stop the vast majority of discharges of effluent into the Thames is 90% complete and will cost a total of £4.5 billion, an investor report revealed today.
The 15-mile tunnel will start diverting sewage away from the river next year and is expected to be fully operational by 2025 according to Tideway, the company behind the infrastruture. The latest estimate of the final cost is a 2% increase on the previous figure.
When it was first announced in 2014 the cost was estimated at £3.5 billion.
Tideway said the impact on water bills would be unchanged.
Tideway said: “When fully operational in 2025 the new infrastructure will capture 95% of overflows from London’s sewerage network, dramatically improving the water quality of the Thames and delivering significant environmental benefits.”
An average 39 million cubic metres a year of water contaminated by sewage is routinely pumped into the Thames when it rains to prevent flooding
