One Tylorstown resident said opening his front door was "like a river flowing out of my premises onto the road".
A man whose house flooded 18 months ago faces replacing his belongings all over again after torrential rain destroyed the downstairs of his home.
Robert Evans, from Tylorstown in the Rhondda valley, lives in one of 25 houses that were inundated with water overnight during the extreme weather.
He says that he woke up this morning to find his alarm clock wasn’t working, and discovered his living room and kitchen were knee-high in water.
Mr Evans said the culvert behind his house became blocked, which was allegedly reported to the council.
He said flooding 18 months ago left him needing new flooring and wallpaper, which he is going to have to replace again.
Some parts of Wales, like the Rhondda valley, have seen half a month's worth of rain in 24 hours
Mr Evan fears that climate change will only bring more challenges in future.
"The water is deeper this year than it was two years ago," he said.
"It is only going to get worse."
Councillor Rob Bevan told ITV News that 25 houses in the street along Arfryn Terrace had been flooded in some way.
Cllr Bevan said: "The residents are all very deflated - they have been living with this problem.
"The water level is up to two to three feet in each property. Some have had less, some have had more.
"The level of rainfall is unprecedented. Culverts can block very quickly and the result of that is what you can see today because the water coming off the mountain brings debris the culverts can block very quickly and cause problems."
Councillor for Tylorstown and Ynyshir, Rob Bevan, believes that climate change has a major role to play in the volume of rain that Tylorstown has seen in recent days
Approximately 20 households had been evacuated locally after properties were flooded, according to South Wales Fire and Rescue.
It says it first received reports of the flooding in Arfryn Terrace at around 5:30am on Thursday.
Rhondda Fach Leisure Centre is currently being used as an emergency rest centre for those residents affected by the flooding.
It comes after parts of the Rhondda valley have been flooded multiple times in recent years.