"You don't want to be out there on the lake and the weather changes.
"People don't realise how much the weather can affect such a shallow lake, it only takes wind at 30 knots to see the lake become choppy.
"Our job is to be there to rescue people when things go wrong, but the harbour master is the one who really sees people behaving like idiots.
"It's always just a matter of when, when things go wrong."
Water Safety NZ chief executive Jonty Mills said this summer it wanted everyone to enjoy the country's beautiful waterways, but to keep water safety front of mind.
"Everyone needs to remember the water safety code: Be prepared. Watch out for yourself and each other. Be aware of the dangers, know your limits and avoid alcohol.
"When it comes to keeping kids safe the most important advice is adults need to actively supervise children in or around water at all times.
"Toddlers need to be kept within arm's reach - it takes less than a minute for a child to drown. Avoid distraction – the safety and wellbeing of your child needs to be your focus."
He said it was important to start water safety lessons with children.
"Children can enjoy positive experiences with their parents or caregivers at council aquatic facilities around the country.
"Children should be taught about water safety as soon as they can understand."
Water Safety NZ has teamed up with The Warehouse and Swimming New Zealand to deliver its Water Skills for Life initiative into more primary schools around the country.
"This is all about fundamental water safety skills and risk assessment," Mills said.
"The number one rule to keep children safe in or around the water this summer is active adult supervision at-all-times."
Rotorua preventable drownings 2017:
January 4: Auckland man Colin McCormick, 49, died on Lake Rotoiti after jumping off his boat to retrieve a hat.
January 17: Rotorua man Shilo Charles Paul, 31, went missing on Lake Rotorua after getting into trouble while trying to steal a kayak. His body was found the next day.
February 12: A man fails to surface after going under while waterskiing on Lake Rotoiti. His body is found two days later. His name is suppressed.
The five boating rules for staying safe in the water
1. Take a lifejacket, wear it and use it. The legal requirement in the Bay of Plenty is that people on board a vessel 6m or less must wear a lifejacket, including on a jet ski or if you are being towed.
2. Skipper's responsibility. Make sure you are looking out for everybody on the boat.
3. Always have two forms of communication. Hopefully a VHF radio and a cellphone in a sealable bag so it stays dry. The VHF channel for Rotorua is 02.
4. Check the weather, make sure it is going to stay calm and not get rough once you are out on the lake.
5. Avoid alcohol and drugs, they don't mix well with water.
- Coastguard