A man whose garden wall collapsed into a river has said he is "living in a nightmare".
Kevin Davies from Ystradgynlais, Powys, was woken up at 04:30 GMT on Thursday to an "almighty bang".
"When I looked outside I saw the entire section of the wall had collapsed into the Tawe," he said.
He added neither Natural Resources Wales (NRW) or Powys council had taken responsibility for wall's erosion for 10 years.
NRW has said the wall is not its responsibility, while the council said the wall was the responsibility of NRW because the River Tawe is designated as a main river.
Mr Davies said he first reported his concerns about the wall to both bodies a decade ago, after a sinkhole appeared at the bottom of his garden.
He said: "Natural Resources Wales came out and did an inspection and within a month we had experts taking soil and concrete samples, as well as divers in the river.
"I believe they spent about £30,000 finding out the cause of it and said it was due to the river levels rising.
"This has been going on since, with NRW saying it's not their responsibility and Powys council saying it isn't theirs either."
Mr Davies said he had looked through archives of council meetings and found the wall was built by Brecon council in 1912 following flooding in the area.
"Obviously it's now Powys Council, not Brecon, so they're not taking responsibility," he added.
"We're on a flood plain, but NRW say they don't count the wall as a flood defence, even though that's what it was built for."
Mr Davies said he, his partner and their neighbours were all worried river levels could rise quickly and flood their homes, particularly due to recent extreme weather.
"The last few days feels like we're living in a nightmare," he added.
A spokesperson for Powys council said: "The council was made aware of a wall collapse and local officers attended to assess the situation.
"The River Tawe is designated as a main river and therefore the lead authority would be NRW, so we have informed them of the collapse."
Neil Stoddart, NRW operations manager for land and assets said he sympathised with Mr Davies and would send engineers to investigate.
However, he added: "After considering the matter in great detail and taking legal advice over recent years we do not consider this our responsibility."