In our main bathroom toilet we have a bad sewer type smell that comes out of the toilet area. The smell only happens around 8 or 9 at night at lasts for a couple of hours. The smell happens on various nights as it does not happen every night. I have tried putting Ridx down the drain even though we do not have a septic tank which did not work. Also there is a tub in the room that is not used and I have tried pouring water down the drain to make sure the p-trap is full of water. Are there any suggestions as to what I can do? Please help... the smell is awful.

If the tub isn't used then fill the trap with motor oil so you don't have the worry of the seal evaporating. If the lavatory drain's OK then the wax seal may be faulty and allowing sewer gas to escape. I can't explain why it only happens at night. Regards, Tom

Agrees w/ Tom - might use vegetable oil instead of motor oil. No inherent odor, etc...