Sun, 23 Dec 2012 06:27 UTC
Residents in Ystalyfera spent the night in a leisure centre after 11 homes were affected. Meanwhile, a wall collapsed at the back of cottages in Berw Road, Pontypridd.
Flooding was causing disruption on rail lines between Cardiff and Bridgend and near Caersws in Powys.
There are seven flood warnings by the Environment Agency in Wales.
Some residents have also had to leave their homes in Berw Road, Pontypridd, after a retaining wall collapsed with a "loud bang" overnight.
David Stewart, whose son Craig lives in one of the affected houses, said: "It happened at about midnight.
"It's a row of about 10 miners' cottages, and the wall collapsed. There's a black expanse of rubble and earth.
"The rubble is up to the bedroom windows in some cases, and one kitchen has disappeared. How nobody was killed, I don't know."
He said four houses had been evacuated, and engineers were examining the "precarious" wall on Sunday.
He added: "My son and his partner have a seven-month-old son. They just had to leave straight away. They didn't even have time to grab a bottle for the baby."
Meanwhile, Arriva Trains Wales (ATW) says signalling problems near Cardiff, which affected trains on Saturday, have been resolved and normal services have resumed.
Flooding disrupted services between Cardiff Central and Bridgend, and Caersws and Machynlleth in Powys.
Trains between Cardiff Central and Bridgend were temporarily suspended but services were reinstated, subject to a diversion.
Replacement road services are also running between Machynlleth and Caersws.
Rail services between Bristol Parkway and Cardiff Central could be delayed by an hour.
The number of flood warnings has been reducing but they are still in place for: The River Wye at Glasbury, the Ely at Ely Bridge in Cardiff, and also at Peterston Super Ely; the Dyfi valley; River Ritec at Tenby and the Lower Dee Valley from Llangollen, Denbighshire, to Chester.
BBC Wales weather forecaster Derek Brockway said in the 48 hours to 06:00 GMT on Sunday, rainfall totals in Wales ranged from 14mm (0.6in) to 60mm (2.4in), with Mumbles near Swansea one of the wettest.
He said the weather would be much drier on Sunday with the wind slowly easing.
Residents were being let back into homes in Ystalyfera to check possessions, with South Wales Police saying four homes remain evacuated.
Mid and West Wales Fire and Rescue left the scene at 03:00 GMT.
Residents are either staying with relatives or have been provided with accommodation by the council.
A structural engineer is due at the scene.
In Llancarfan, in the Vale of Glamorgan, staff and drinkers at a pub rescued a motorist from the River Carfan on Saturday afternoon.
The woman was driving through the village, which has a ford through the river, when her black Mini ended up in the swollen waterway.
Sue Millard, who runs the Fox and Hounds Inn with husband John said a neighbour raised the alarm as the car, with the woman trapped inside, floated down the river backwards.
She said: "It got stuck on the bridge by the village hall. Luckily for her, it stopped on the middle section as opposed to the two archways either side."
She said the neighbour and a regular broke the passenger window with a ladder which they then put into the car.
One of the men climbed along the ladder and coaxed the traumatised woman out of the car.
The car has since become stuck under one of the smaller archways.
Mrs Millard added: "She was in a total state of shock and distress as you can imagine. I don't think she will be doing that again.
"None of the villagers would have driven through the ford with the river like that, especially not in a mini."
Elsewhere, about 25 firefighters from Mid and West Fire Service were called to 30 flooded houses in Kingrosia Park, Clydach, Swansea, on Saturday afternoon.