The death of a toddler in a Gore wastewater pond has been labelled a tragic situation for a family and a community by a water safety group.
A three-year-old boy was reported missing on Tuesday night, and his body was later found in a pond at the treatment plant.
The council has now ordered an urgent review of the security and fencing at the ponds, reported Stuff.
The wastewater ponds are at the southern end of Gore, and are surrounded by farmland.
Water Safety New Zealand chief executive Jonty Mills said it was an absolute tragedy.
"Sadly it is the second toddler under five that has drowned in the South Island over the summer," he said.
Toddler Grace Marie Griffin was found in a water race in Ashburton on January 6, and later died in Christchurch Hospital.
Mr Mills said any waterway presents a potential risk, especially in rural areas, and awareness of hazards is key.
"In rural areas if you are visiting or on a farm, it's about being aware of potential hazards and whether there is any restricted access or signs," he said.
"For toddlers, it's about constant supervision - but we all acknowledge how quickly toddlers can disappear, particularly when they are mobile."
Mr Mills said drowning is a complex problem in New Zealand.
"Our country is full of magnificent waterways that we all recreate in in whatever shape or form, and its not realistic to expect that every waterway in this country which is potentially is a hazard is restricted or fenced, and particularly in those rural areas."
In 2018 three under-five year olds drowned in preventable incidents, one in a pond, one in a drain, and one in a home pool.
In 2017 there were seven preventable fatalities involving under-fives, with five in home pools and two in ponds.