Berkshire floods: Flooding fears as rising waters expected
Residents have been warned to expect further flooding in east Berkshire with more rainfall forecast.
Prime Minister David Cameron said: "I've said to the Environment Agency and the gold commander, water levels are going to rise, let's identify communities that could be at risk."
The agency said it was focusing on putting in flood defences in areas including Old Windsor and Datchet.
Seven severe flood warnings remain in force from Old Windsor to Wraysbury.
The Prime Minister added: "Part of the problem in the Thames Valley is because there's so much base water in the ground, if you pump the water out it comes back up.
"These are going to be very difficult times."
More than 1,000 homes have been flooded along the Thames in the past two weeks.
David McKnight, of the agency, said: "I don't want people to become complacent, we have more rain coming so we're not going to let our guard down."
Windsor and Maidenhead council said more than 20 portable toilets had been delivered to flood-affected areas where people were unable to flush due to the high levels of water.
Leisure centres and public halls have also been opened to the public.
'Don't do it'
In flood-stricken Wraysbury, Royal Berkshire Fire and Rescue said it had carried out more than 100 rescues since Monday.
Chief fire officer, Andy Mancey, said: "The scale and severity of this flooding is having a massive impact across the entire county.
"We are still seeing people trying to drive through flood water and we can't say strongly enough - don't do it."
Flooding in the lineside railway signalling equipment at Maidenhead in Berkshire has caused disruption to First Great Western services between London Paddington and Swindon.
Julian Burnell of Network Rail said: "Only one train can enter a particular area at any given time, and no other is allowed in until we have visually verified that the trains has cleared that area."
Also in the Thames Valley, flooding at Datchet and surrounding areas meant buses have to run instead of trains between Staines and Windsor and Eton Riverside and this section of line is not expected to reopen until Friday.