Michael Walker-Mitchell was allowed to roam the streets of the East Coast settlement of Te Karaka, as long as he watched out for dogs, kept off the road and was home by dark.
Good rules, but "daredevil" Michael was just four and didn't stick to one of them - to stay out of a property 108m from his home because there was a disused water tank there.
Four days after his fourth birthday he wandered on to the property, into the 1.8m deep tank and drowned.
Hastings Coroner Chris Devonport, in a report released today, found Michael died of drowning last June 4.
His family raised the alarm when he failed to return by 5pm, having last been seen at 3.30pm. Others in the village were called, and police were notified at 7pm. Michael's body was found just after midnight, submerged in the water tank.
His father, Michael Mitchell, told the coroner the preschooler knew not to go into the property.
"I told him not to go in there. My aunty stays across the road and she always tells the kids to keep out of there.
"The gate's always down and horses run in there all the time. As far as I can remember, that tank was uncovered. That's why everybody was told to stay out of there."
Michael usually played with his trucks in a drain outside the family home or went to his cousins with his five-year-old sister, Mr Mitchell said.
"Everybody knew him in the village, most were related to him," he said.
"There's a kind of attitude that you look after each other's kids. Michael was always told not to take off by himself but he would.
"We had rules, like watch out for dogs and never walk on the road and be home before dark."
Mr Mitchell described his son as "a bit of a daredevil", always climbing on cars or running around.
Mr Devonport said the property the water tank was on had a gate but there was a gap in it which an adult could walk through.
The tank was 1.8m deep, 5.3m long and 2.8m wide and set into the ground but was not classed as a swimming pool and therefore not required to be fenced.
However, it was clearly a hazard to small children - "and that fact appears to have been known", Mr Devonport said.
"However, the tank was not adequately fenced off or covered to eliminate the hazard. The only action taken to reduce the danger to small children appears to have been to instruct them to not enter the property.
"Tragically, in Michael's case, that was insufficient."