At 1pm, police told the club's callout squad that the family had been washed out to sea.
A surfer helped two of the swimmers into the shallows and the third person was able to swim out themselves.
"When our lifeguards arrived the mum particularly was in some respiratory distress," Mead said.
The lifeguards administered first aid while the Auckland Westpac Rescue Helicopter was called. The mother was flown to Auckland Hospital in a serious condition.
The teenagers were treated at the clubhouse and taken to hospital. St John Ambulance said they were in a moderate condition.
"These guys were just really lucky because two of our guards were literally across the road from the club when the callout came," Mead said.
"That is relatively abnormal during the week, people tend to be at least 10 to 15 minutes away and they still have to get onto the beach.
"If that luck isn't around on the day then the outcome for someone getting in trouble when they are not patrolled is not good."
The rescue capped a bad week on the west coast beaches.
Two people died and three separate rescues took place.
"It is really, really disturbing to us - we're not even into summer yet," Mead said.
"Unpatrolled beaches on the west coast should be avoided."
A woman died at Whites Beach in Anawhata after falling into the water on Tuesday. On Monday, a fisherman went missing of Kauwahaia Island at O'Neills Beach.
Four swimmers were rescued at Piha yesterday after being sucked out through the Keyhole, and swimmer needed help at Muriwai Beach.
"We are pulling volunteers from emergency call-out squads to place themselves at risk to help these people," Mead said.
He said O'Neills Beach had the "perfect storm" of risks for inexperienced swimmers.
It was enclosed by rocks on both sides, creating significant water movement and rips. It also had a sandy bar in the middle of the bay, which was continuously shifting because of the large volumes of water propelled by the heavy surf.
Surf Living Saving officials this week said the number of people heading to the beach has dramatically increased because of the end of Covid-19 restrictions and the warmer weather.