Question: what requirements are needed to be a lifeguard?
Answer: You need to be 16+.
Must be able to jump, much preferably, dive into deep water. ... 
Swim 50 meters, two lengths of an average pool, in 60 seconds. ... 
Swim 100 meters continuously, at your own pace, on front and back in deep water. ... 
Tread water for 30 consecutive seconds.