Plaid Cymru MS Leanne Wood has called for an “urgent inquiry” into how this could have happened again in such a short space of time.
One man whose parents live in Pentre said they were only just getting ready to move back in after Storm Dennis but now he thinks they may not want to return. Steve Hughes said this round of flooding is "the nail in the coffin" for his family.
Sion Tomos Owen, who lives near the area, said: “These families and homes still haven’t recovered from Storm Dennis and are still in lockdown, in other family members homes, because of it.
“How can this happen after only 45 mins of heavy rain? It’s coming up through the manholes.”
Areas worst affected appear to be Pentre, Maerdy and Treherbert.
Aysha Powell, who lives on Pleasant Street in Pentre, told ITV News she was currently undergoing renovation work in her house after it was damaged by the floods earlier this year.
She had recently had a new kitchen delivered as part of that work and said she spent last night trying to save it from water damage after her garage was flooded.
"I am really upset. It's just a shock it's happened again in June.
"I've been quite lucky - there are some houses that just finished work and they've been devastated again. We are going to have buy flood barriers for our homes.
"You see people out on the streets crying but neighbours have been fantastic. Even though you're meant to keep two metres apart, you can't. I had eight people in my garage trying to save my kitchen last night."
Leanne Wood, MS for the Rhondda has expressed her anger at how this could be happening to her constituents for the second time this year. She said "it is not acceptable" and "urgent" action is needed.
She claims sandbags were not initially widely distributed by the council and people had to rely on donations from builders for the first 12 hours.
“What is needed is urgent assistance from the various authorities to prevent further flooding. Sandbags – which were not forthcoming from the council initially – need to be delivered to every home that is at risk of further flooding throughout this spell of heavy rain.
"The drains also need cleaning urgently as this has been identified as a cause of flooding in many areas."
The Environment Minister Lesley Griffiths issued a statement and said her "thought are with the communities of RCT" and the Welsh Government are in close contact with Natural Resources Wales to "understand the cause of flooding and related impacts."
“There’s still a risk of further localised flooding so I urge people to stay vigilant and keep an eye on the latest forecasts and flood warnings on NRW’s website.”
Leanne Wood is also calling for an inquiry into why the same south Wales Valleys areas are so vulnerable to flooding.
It is disappointing that [an inquiry] is yet to be completed but the events of the last 24 hours shows it cannot be delayed further if we are to prevent any further flooding of Rhondda communities because there is clearly a major issue here.
A vicar from the local area said many of the houses here have flooded three times in just a few months. He said this is "unacceptable".
Reacting to the news of more flooding, Rhondda MP Chris Bryant said despite being "a resilient community" he did not know if they "can take much more."
Rhondda Cynon Taf Councillor, Andrew Morgan, said: “As the Leader of the council, I recognise that residents will want answers and will also want to know what can be done to stop this from happening again."
From the information I received today from Officers of the council, a culmination of factors beyond the control of the council contributed to this flooding. It does not appear that the culvert, which contributed to the flooding last February, was the cause of yesterday evening’s flooding in Pentre.
“The council will continue to work with Welsh Water and Natural Resources Wales to reduce the risk of this happening again and to provide as much resilience and security for residents as is practicably possible.
“The council will do all it can to support residents to recover, including providing financial assistance, as we did following Storm Dennis.
“It will also be important to provide the opportunity for residents to receiveanswers to the questions that they have rightfully and understandably raised,and to ensure that the community is engaged in moving forward.
“To that end, I have asked Officers to urgently bring forward a report that looks into the causes of flooding and identifies what action needs to be taken.”
Michael Evans, Head of Operations South Wales Central for Natural Resources Wales, said the team has been handing out sandbags to residents and placing them on their land "to help channel any water from the mountain away from the village should there be more heavy rain."
Mr Evans added: “Inspections carried out on the culvert on the mountain above the village show no signs of blockages, indicating that flooding in Pentre was caused by the sheer volume of rain that fell over a short period of time which overwhelmed the drainage system.
“Every home flooded is a personal tragedy and those affected by Storms Dennis and Ciara in February will feel the impacts of yesterday’s storms even more deeply. We want to reassure these communities that NRW is committed to supporting local authorities to recover from these events and to work together to managing flood risk and building Wales’ resilience for the future.”
Natural Resources Wales described Storm Dennis as an "extremely severe weather event" with the River Taff at Pontypridd reaching its highest level for more than 40 years.