"Horizons says the culvert is owned by the Whanganui District Council and it's their issue to resolve, Whanganui council says Horizons is responsible for flood protection," Mr Buchanan said.
Mr Anderson said he would go into bat for the residents during next week's annual plan submissions where he will push for bigger culverts.
"It's been an ongoing issue, the culverts are too small," Mr Anderson said.
"They have a propensity to block and once that happens the water can't get out ... and overtops the road.
"It's pretty simple to me what the problem is ... you don't need to be an engineer to work it out."
Mr Anderson said even when the culverts are not blocked heavy rain can tax the culverts.
"The frustration is getting people to understand that.
"It is unsatisfactory and not good enough. No-one is taking ownership of the problem."
Whanganui East residents affected when the Matarawa Stream floods were asked in March if they were willing to pay an average extra $60 to $80 a year to Horizons to clear the obstacles from the stream as it runs through their suburb.
If they are not willing to pay, Horizons will not do the work, they were told.
Mr Buchanan said that would not fix the problem as it was the culverts that needed replacing.
Submissions to the district council's annual plan will be heard over two days beginning Tuesday.
