Work continued overnight to make sure hundreds of homes in Kenley and Purley continue to be protected from flooding.
Flood barriers have been installed to divert thousands of litres of water away from about 400 vulnerable homes and businesses.
And with more heavy rain forecast the decision has been made to turn two more areas into ponds to hold flood water.
The sites deemed most suitable to create these extra flood defences are the car park at St John the Baptist Catholic Church, in Dale Road, and the school field alongside the Harris Primary Academy, Kenley, which is currently closed.
Parishioners will still be able to use the church.
Council leader Councillor Mike Fisher said: “We are in a critical situation and this means having to make extremely difficult but necessary decisions.
“If we don’t act now hundreds of homes in the area could be flooded and we are trying to stop that from happening.
“The sites will help us to manage rising water levels, and we have the full support of those concerned to undertake this work.
“We hope too that residents will understand this short-term inconvenience is about protecting a lot of people, their homes and their livelihoods.
“Many teams from across the council, emergency services and local water companies continue to work around the clock to help Croydon stay on top of things, and I’d like to thank them all for the tremendous collective response to hold the waters at bay, protect property and keep people safe from harm.”
- Council to launch High Court legal action in bid to stop 'dangerous' Croydon Cruise
- CBeebies stars sign up for Croydon panto
- Political heavyweights and best sellers line up for Dulwich Literary Festival
- Boundary commission slaps down Conservative proposals to cut number of Croydon councillors
- 'Long term future' of nurseries could be at risk from proposed flat-rate funding, London Councils warns