In a report released last week entitled 'Crazy Paving', the assembly revealed that two thirds of the capital's front gardens have been paved over - a major contributor to the capital's flood problems, it claimed.
'Rain not absorbed runs into the already creaking Victorian sewerage and drainage system. In recent years flash floods meant tonnes of raw sewage were dumped in the Thames, which turned into localised flooding as rivers burst their banks,' said a spokeswoman.
The assembly wants the mayor to promote environmentally friendly alternatives such as gravel, and are also lobbying to reform the planning laws.
The capital's residents are choosing to pave over their front gardens to park their cars, to have a minimalist garden or because they do not like gardening, said Assembly environment committee chair Darren Johnson.