Pierre has recently begun peeing while standing up in his litterbox, getting pee on the wall behind it (and under the box). This used to be an occasional thing and is now once or twice daily. I've been able to deal with the sanitation issue using strategically placed puppy pads, but I'm wondering if I need to have the vet examine him? He's 2-3 years old, neutered, no apparent health issues, doesn't make any sounds while peeing. There is another male cat in the house (slightly older and also neutered), they've lived together for almost two years with no problems. There are three litterboxes.
