My son took his nplq several years ago aged 18 as something to do whilst trying to get a proper job. Four years on and he's still doing it. He works for Nuffield Health and whenever they are short staffed with lifeguards, which is all the time, he can't take breaks which are supposed to be compulsory legally. Try sitting in that chair for eight hours in the warm air and not fall asleep. It is usually very boring as has been said, you have to berate stupid parents throwing their children in the air or rescue the odd baby as it rolls into the water behind mum sitting on the pool side talking to her mate. The worst one was when a man in his 20's collapsed after a gym workout followed by squash session and the other 16 year old lifeguard on duty with him froze, leaving my son to do all the work on his own till someone else appeared. Both cpr and defib were used. The ambulance arrived thirty minutes later after constant treatment by the staff, but he was pronounced dead on arrival at the hospital. Please be aware, these things happen, albeit not every week, but you have to be prepared for this mentally as well as physically.
Having said that, he usually works a 40plus week on minimum wage but is on a zero hours contract and is never paid the correct amount for the hours he has done. They are always promising to correct it but six months on and he's still waiting. It's probably safer both legally and financially to work at a council pool as private companies abuse their staff with only profit on their minds.