Stepson floods my bathrooms

My bathroom was flooded today. Apparently, my stepson doesn't shut the shower curtain all the way. There was so much water that it leaked through the floor and down to the lower floor bathroom/utility. It's a good thing the basket of dirty laundry caught a lot of water. Otherwise, instead of 1/4" flood of water around the downstairs bathroom/laundry, it would've been gushing. I cleaned that up and sent my husband, stepson's dad, to clean up the bathroom that my stepson had used - the source of the flood! I mean, there was A LOT of water. Half his shower must've come out of the tub!

*sigh*

My younger kids who take showers on their own know to do this. You'd think a kid his age would already know this.