If you have been on the road awhile, have not used your shower for a
while, there is a great possiblity that the drain has dried up. This
is not uncommon and a good place for the methane gas to come from. It
smells terrible as you say and can be controlled by keeping water in the
drain. Not a lot just enough to prevent the gases from escaping the
holding tank (even if it is empty) to the inside of the GMC. Chuck
while, there is a great possiblity that the drain has dried up. This
is not uncommon and a good place for the methane gas to come from. It
smells terrible as you say and can be controlled by keeping water in the
drain. Not a lot just enough to prevent the gases from escaping the
holding tank (even if it is empty) to the inside of the GMC. Chuck
