Kirry, J is not very confident with water and we've been through a few bath rejections with him. The root of it has been that he got a scare in the bath, - too big a splash or slipped over, something like that. We have just had to start from scratch and ease him slowly back in. For instance when he slipped, we let him stand in the bath and sit only when he felt like it, we would suggest to sit, but let him actually do it, after a week or so he was back to sitting.
Another time, he wouldn't get in a he slipped on the way in, so we would let him go in his own time, and if it was taking too long make up a song about the boy called Jarrah who hopped up on the step and went into the bath, as he needed to hop up we put our hand and help him up, sometimes that worked he would be enchanted by the song.
Even now, if he has had a rough day, he doesn't want a bath, so we do a quick wash over , that's maybe once a fortnight for a rin of a few days.