Thames Water is considering a new area as a key construction site for its £3.6bn tunnel to help reduce the amount of sewage polluting the River Thames.
The land at Chambers Wharf in Bermondsey is being considered as an alternative to using King's Stairs Gardens, which prompted opposition.
The 20-mile (32km) Thames Tunnel would run from west to east London collecting sewage discharge triggered by rainfall.
Thames Water says it will cut pollution in the Thames for 100 years.
Residents fear the works will take over parks and protected spaces for years, reduce house prices and leave ugly concrete shafts and service buildings.
Thames Water had been considering King's Stairs Gardens in Rotherhithe as a preferred shaft site but local residents, along with Southwark councillors, opposed the plan as it was a green site.
Phil Stride, Thames Water's head of London Tideway Tunnels, said they had bought the land at Chambers Wharf but using it was still only a possibility.
"I must stress that this does not mean we will definitely use it or that we have discounted King's Stairs Gardens," he added.
"When Chambers Wharf came up for sale we had to act quickly to ensure we could consider the land in detail as a potential site. It is vital that we keep our options open.
"There is still a lot more work to be done, including further discussions with local communities, before we make any final decisions about the construction sites we need."
A Southwark Council spokesman said it was led by what the residents felt about the site.
"Whatever their (Thames Water's) choice is we will be working with them to minimise the impact. We want a site that doesn't affect our residents or schools."
Thames Water had earlier estimated the cost of the tunnel could result in bill increases of about £60 to £65 per year for its customers.
The sewer would be up to 75 metres below ground, broadly following the route of the River Thames.
A company spokesman said the tunnel was needed to capture the 39 million tonnes of untreated sewage which is discharged each year into the river.
Thames Water hopes to submit a planning application in 2012, with construction due to be completed in 2020.
- 15 January 2011
- 8 September 2010
- 17 November 2008
- 8 August 2008
- 20 July 2005