When I was a teenager I was in Boy Scouts. Every year we went to a summer camp that was on the edge of a large pond [1]. And one of the strictest rules there was that you were not allowed in the water until you'd passed the swimming competency test (and you had to pass it again every single year), and the main swimming test was that you had to swim laps in their roped-off section of the lake without pausing until you'd swum for at least half of the distance across the lake (thus ensuring that if you were to be dropped smack dab into the middle of the lake, you could swim out). We had to do this even though most scouts never even had a reason to go outside the small roped-off section and thus would never be required to actually swim to shore.
I also remember one year doing a lifeguarding merit badge where we did various things like tread water for an excessively long period of time, practice towing other people to shore, and even a bit where we had to jump into the water fully clothed in jeans and a long-sleeved shirt and learn how to float regardless (basically by inflating our shirt with air). That stuff was hard. Also one bit where we started on shore, fully-clothed including jeans, socks, laced-up boots, etc, and had to ditch as much clothing as possible and run into the water within an extremely short period of time (the idea being if we saw someone drowning, we had to be able to get in the water to effect a rescue as fast as possible).
[1] New England has a habit of calling large bodies of water "ponds" even though most other places would call them lakes