What happens when I overfill my RV’s holding tanks?

What happens when I overfill my RV’s holding tanks?

What happens when I overfill my RV’s holding tanks? Well, if you are lucky, any overfill in your black or gray tank will travel up your vent pipe and make a mess on the roof. However, the answer is a bit tricky and depends on the exact plumbing setup of your RV....