In Wanaka, swimmers have been encouraged to seek out local knowledge before swimming.
"One drowning is too many," Coastguard Wanaka Lakes president Jonathan Walmsley said.
For many lake users, it was not stupidity that got people into trouble, it was having no idea or awareness "what they were doing was unsafe", he said.
He shared the example of a boat creating a large wake on a flat day, resulting in rowers unable to take to the water.
It was important to have situational awareness when on or around water, he said.
This extended from boat users to those choosing to paddle on, or swim in, the lake.
"People forget how powerful water is."
Mr Walmsley acknowledged the "almost rite of passage" to float down the Clutha River.
"While this is fantastic fun, every so often this goes terribly wrong," he said.
Preventive measures such as life jackets and adequate awareness of the river were essential before going down it.
"You can’t see what’s under you," he said.
This advice was echoed by Wanaka Lake Swimmers Club president Camille Gulick.
"Be aware of hazards above and below [such as visible and hidden rocks and overhanging willows] and safely move over them," she said.
Lake users should be mindful of where water was flowing in and out of, because of the variable temperature changed, she said.
She used the example of the Matukituki River inlet, where temperatures could sometimes be "in the single digits, even in summer".
Her advice was to avoid it, and if unsure, seek out local swimmers.
People should go into new areas with people who went frequently and knew the lake.
Some of the notable differences between ocean swimming and lake swimming included buoyancy and varying temperatures.
‘Never feel pressured to do something or take a risk, just because someone else is doing it," Ms Gulick said.
Mr Walmsley agreed, referring to examples of water-related incidents where the "peer pressure" of not calling for help had left people in trouble.
Non-urgent assistance call outs often involved middle-aged men who were solo fishing off their boat and had been drinking, Mr Walmsley said.
Both agreed a key thing lake users had to be mindful of was the reality of cold temperatures.
"Even if it’s 17degC in the lake, you can get hypothermia if you stay in too long," Ms Gulick said.
After getting out of the water, the body continued to lose heat.
The fastest way to warm up was internally (through hot drinks) rather than the externally (such as a hot shower), she said.
