I'm not sure what diameter the hose is. I keep Tygon fuel line in my shop of various sizes and used it since there will be fuel vapors there.
With that said, please don't route the line where it will be close to heat and use a hose rated for fuel or at least fuel vapors. I ran my hose extension up to the back of the seat which is high enough for me. I don't plan on going deep enough for water to go over the seat and this hose is ~6" over the seat bottom.