The capital is "at risk of major flooding" unless something is done to support the over-capacity sewer system, according to a new report.
The new research supported by the Major of London, Thames Water, the Environment Agency and London Councils calls for the capital's public spaces to be transformed into green areas which will help absorb surface water after rainfall.
17% of permeable ground has been lost in London over the past 40 years as homeowners chose to cover their previously green lawns with concrete. This means that water which used to be absorbed is now directed towards sewers which are unable to cope with the strain.
The planned super sewer under London has been hit by two legal challenges. The Thames Tideway Tunnel was granted planning permission last month - with Thames Water claiming it was needed to replace ageing Victorian sewers. But Southwark Council and a group of water industry experts have lodged applications for judicial review.
Southwark Council says the work would have a "devastating impact..on the lives of the thousands of people who live, work and go to school around the proposed Chamber's Wharf tunnel drive site."
Thames Blue-Green Economy, a coalition of water industry experts, claims the Government is in breach of the public participation requirements under the Environment Impact Assessment Directive and British Law.
Phil Stride, Head of the Thames Tideway Tunnel at Thames Water, says the company may not stand to make any profit from the project.
Thames Water has offered the following response to the claims from Hammersmith and Fulham Council:
Hammersmith and Fulham Council has accused Thames Water of ripping off its customers.
They claim that the super sewer isn't necessary - and that the company is being motivated by financial gain, rather than the environment.
The council argues that there are alternative solutions to the capital's sewage overflow problems - new drainage systems, for example, that could minimise the amount of fresh rain water entering the sewerage system.
They also claim that Thames Water stands to make "colossal returns at bill payers' expense".
Watch Thames Water's video below to find out about the construction of the super sewer.
THE CURRENT SITUATION
At the moment, our sewers fill up when it rains - and untreated waste water spills out into the River Thames.
THE PROPOSED SOLUTION
The new "super sewer" would divert the waste water away from the river.
When it rains in London, our old Victorian sewers fill up.
If the excess water isn't discharged somewhere, the sewage could back up into homes and streets. So, instead, it's released into the River Thames through "combined sewer overflows".
Thames Water says that, in a typical year, 39 million tonnes of untreated sewage flushes into the river. And - as the population of London increases - this problem is set to get worse.
So, they want to build a massive new sewer to increase the capacity of the system - and help clean up the River Thames.
Watch Thames Water's video below for more information.
The Thames Tideway Tunnel will be a new "super sewer", the width of three London buses, which will run underground from west to east London.
It will be around 20 miles long - and will broadly follow the route of the River Thames, connecting up to 34 sewer overflows.
Sewage, which would otherwise spill into the River Thames, will then be captured in the new tunnel and transferred to a waste water plant in Beckton to be treated.