How do I keep these small little snakes out of my backyard and out of my pool?

My husband handled the yard work and each week he finds a snake or two in the pool traps. Usually they are dead but occasionally he has to kill them. Today he actually found 2 in the trap and one in the pool swimming around! I’m completely horrified! Although he tells me that the snakes are always very small (5–6”), I’m concerned about whether they’re babies or if they’re just garden snakes. I have no clue. Somebody with a pool please help! We just bought this house in September and I don’t want to leave but I also don’t want to pay for a house that I can’t enjoy!