There had been e-mails sent his way over the past few days, advising he had been picked to represent his country in the 73kg class, but his computer had been hacked and communications had gone awry.
"So I didn't know," Mr Waterhouse said.
His coach began getting in touch with his brother and others back in Samoa asking why Abner was not responding - so they began making inquiries, tracked down where Abner had been working, and finally a call came through.
"It was from coach - he asked me why I wasn't answering his e-mails - he said I had qualified for the Olympics."
He was, naturally, slightly stunned.
"I thought I might have had a slight chance of making it," the quietly spoken 31-year-old said, adding one of the first things his coach asked was "are you still in good shape?"
He said yes, he was.
His days of picking, and especially vine work which used muscles crucial to judo competition, had kept him fit and strong.
It was good news for the man who began learning judo at the age of 12, and started competing at 15, back in his village of Falealili.
For it was the second time he had got such a call, although his planned journey to London for the 2012 Olympics as part of the judo team was cruelly ended when he suffered a serious injury to the anterior cruciate ligament in one knee.
"So this is so good," he said, adding with a smile that yes, he intended to be very, very cautious in his build-up so as not to miss this one.
He was also proud to be following his elder brother Trivolta who represented Samoa at the 2000 Sydney Olympics.
"He was the fourth person to call me to ask if I was in shape," he laughed.
And in time to come his younger 18-year-old brother who had also taken up judo may make it a family trifecta.
"I taught him everything he knows," Mr Waterhouse said with a smile.
Drew Bibby from Thornhill Horticulture said the company and his workmates were very proud of him.
"It's great news," he said.
There had been a lot of hugs and handshakes from his colleagues before he left for the airport.
"They were happy for him but sad to see him go - he's such a really nice guy."
Mr Bibby said they would be putting a bigger screen in place for the August games and would be cheering their workmate on.
Mr Waterhouse, who will be under his competition name of Benjamin Waterhouse, said he would compete as strongly as he could amid tough competition, especially from Japanese, Ukranian and French judo competitors, but was determined to come back to New Zealand again for a second time - with a medal.
"It is going to hard," Mr Waterhouse said.
There were no nerves at this stage but he reckoned that would change "when I'm over there and I'm on the mat".
Mr Bibby paid extra tribute to Air New Zealand which made special late arrangements to find him a seat to Auckland and then quickly on to Samoa.
