10 year old peeing on the floor next to the toilet, says he thought it would just disappear?

I’m going to try and give as much information as possible so I can maybe get a informed response.My oldest is 10 years old, doesn’t have any major health issues but does have adhd. He’s a terrible sleeper and takes melatonin for it. He’s a skinny kid with a high metabolism, he’s exactly how I was when I was his age. He has two younger siblings aged 6 and 2.For really as long as I can remember he’s accidentally peed next to the floor and I hadn’t really put my thought into it because he’s a kid and accidents happen. But my husband said that he walked into the bathroom and there was a puddle of pee right next to the toilet and upon him talking to our son, our son said that he just thought it would disappear. He basically thought that if he left it, it would go away or I’d clean it up. Now we have made him clean up his mess before because we feel it’s important that he realizes that it’s his mess and it’s his responsibility. But he’s done this off an on since he was about 7 or so. It’s just odd to me that he literally thought it would go away. And it really has been an issue latelyI googled possible reasons why he’s doing it and of course it could be an undiagnosed reason. I’d like some insight if anyone has any on maybe why he’s doing it? via /r/Parenting https://ift.tt/39ndjCt