A toddler has died in hospital after falling into a home fish pond in Merriwa last weekend.
Ambulance crews were called to a house about 2pm where a 19-month-old boy had been pulled unconscious from the pond.
He was rushed to Joondalup Health Campus then taken to Princess Margaret Hospital, but died.
A PMH spokeswoman confirmed the case had been referred to the coroner.
Madeline Righton from the WA Royal Life Saving Society said it was the fifth toddler drowning since November, 2012.
The coordinator of the society's Keep Watch toddler drowning prevention program, she said it was an extremely worrying trend.
"In the 2011 drowning report, there were 44 hospitalisations in the 0-5 age group - that figure has increased by about 10 times over the last five years," she said.
"One of the deaths came in the shower. A child can drown in under 3cm of water, it's just a matter of turning your back.
"Even if they don't drown, immersion can cause permanent damage."
Ms Righton said the keys to toddler water safety were close adult supervision, pool fencing and emptying items such as inflatable pools, buckets and baths.
For Kidsafe chief executive Scott Phillips, it was another tragic reminder of the hazards that could be found in backyards.
"It's really important that any bodies of water are either out of reach of children or protected by some sort of barrier," he said.
"When a toddler drowns, it's silent."