A council leader said more money is needed for flood prevention systems to reduce demolition and cleanup costs.
Wales was interrupted after days of heavy rain.
Several flood warnings were issued and a weather warning was issued for rain until noon on Saturday.
Andrew Morgan, leader of the Rhondda Cynon Taff council, said there was a need for “continuous investment” in response to the floods that “drained” the councils’ resources.
Transport for Wales said flooding had disrupted some trains between Cardiff and Bridgend county on Saturday.
On Thursday, electricity was cut to homes, people were rescued from cars, and properties were damaged by the constant rain.
Mr Morgan, who is also chairman of the Welsh Local Government Association (WLGA), said that although work over the past few years has been successful, there are “many” culverts that need improvement.
“Unfortunately, more than 20 properties were flooded, both vents were drowned by the volume of water, the rubble washing out of the mountain. So it shows that we still need to make this investment,” he said.
“Climate change is happening and we’re seeing floods more often. But especially the density of the air is really changing.”
Much of Wales experienced heavy rain, although Rhondda Cynon Taf (RCT) was one of the worst affected areas.
Mr Morgan said the cleanup was “relatively small” on this occasion, affecting 26 homes in his area.
“Probably tens of thousands” [of pounds worth of damage]said.
“What we needed to do was reroute most of our contractors and highway staff who would be working on other things. So yesterday’s staff who needed to fill potholes or make new pathway plans or re-pave roads.”
He said the first thought during a serious flood event was to respond to the emergency, but that it was a “concern” that this would mean less funding for other important services.
Mr Morgan said that while more than £14m has been spent on infrastructure upgrades at the RCT since Storm Dennis in 2020, £20m has been spent on storm repairs over the same time period.
He said more than £6.4m of Welsh government funding for the RCT was secured after Storm Dennis, as well as around £3.9m for flood reduction efforts.
The Council has also received more than £8m from the Resilient Roads Grant for targeted flooding work over the past three years.
Mr Morgan said preventative investment was “vital” and added: “What we don’t want to do is send teams to clean up the mess.
“What we have to do is flip the money and spend more on prevention and upgrading. This cannot be a short-term fix.”
Mike Evans of Natural Resources Wales said climate change is “no longer a topic of discussion…it’s happening”.
“We had the biggest floods we’ve ever experienced in 2020. 2022 was the hottest year on record and also the biggest drought in Wales,” Evans said.
“The storms we experience are more frequent and larger. So we will experience more frequent flooding and have to deal with it because we cannot be expected to build higher and higher flood defenses.
“We will build defenses to protect the people at highest risk. But as climate change escalates, it’s nearly impossible for funding and interventions to keep up with the increased risk.”
The WLGA said the past decade has seen “unprecedented extreme weather events” putting “enormous pressure on our communities, services and infrastructure”.
He said: “The impacts of resources on local government and partner organizations are enormous, not only before and during an event, but also months later.
“There is no doubt that the future budget tightness will put more pressure on technical services that have already pushed their limits.
“It is important to note that adapting to climate change will require large amounts of financing, which in itself is not sustainable.
“As a collective, we are therefore looking for new ways to build resilience and adapt to these influences.”
The Welsh government said it has invested more than £390m in flood and coastal erosion risk management through two programmes, reducing the risks faced by more than 47,000 properties across Wales.
He added that an additional £71m was spent on such work across Wales this fiscal year through local authorities and Natural Resources Wales.
A spokesperson added: “This includes building new flood assets, maintaining existing assets, developing future plans, natural flood management, property flood resilience measures, mapping, modeling and awareness raising.”