Can't he just jump in every now and then? Say to the home owner, "Opps, sorry, I slipped. I'm okay though, so I won't sue."
Some of his jobs require him to get in the pools, but most times he just works on filters out of the pools. But if he wants to jump in a pool to cool off he can. Last year when it was so hot he did a few times. I’m sure he’ll do it again this summer. I hate his job, but he loves it. He works hard.