A 15-year-old Christchurch schoolboy drowned when his family misread a sign, assuming that because it showed a person swimming it meant the river was safe.
Since Haenga Puhuipuhi-Albert's death in February 2010, Environment Canterbury has replaced the sign at a bridge over the Waimakariri River in North Canterbury.
But when Haenga was swimming at the river with his family on a sunny afternoon the sign on the bridge read "Think water safety if swimming" showing a large picture of a swimmer in an arrow pointing to the water.
A coroner's findings into Haenga's death, released this week, said Haenga's father and stepmother saw the sign but were critical of its clarity.
It was the same spot where, in January 2008, 16-year-old Lale Sioa Taiulu and 26-year-old Larry Pau drowned, after being swept away by strong currents.
In January 2004, 23-year-old Rahmatullah Qambari also drowned near the old bridge.
Since Haenga's death the sign has been taken down and replaced with a large sign on the bridge pile showing that swimming is unsafe.
The updated sign depicted a large yellow and black diamond showing a swimmer with a red cross over it, as well as three other yellow diamonds showing there are sudden drop offs in the water, strong currents and effluent outflow.
Coroner Johnson described these new signs as "very clear".
"I consider these signs will go a long way to prevent future deaths by drowning in that part of the river."
But she further recommended that Environment Canterbury, the Waimakariri District Council and the Christchurch City Council continued educating the public on the dangers of swimming, particularly in that part of the Waimakariri River.