Thursday''s Ask the Experts question from a cleaning professional on the International Custodial Advisors Network (ICAN) "Ask the Experts" page: There has been a strong sewage odor in the public restrooms of the building that we can''t seem to get rid of. This is a retail facility and the strong, unpleasant sewer odor obviously decreases sales. There are sealed toilets, extended vent stacks, working p-traps, no real noticeable causes. What might be the source of this? How can we get resolution to this problem?
There is only one source of sewer gas and that is the sewer. You have checked the obvious. The toilets and urinals are self-trapping and as long as water is visible, the trap is in place. The traps under the lavatories and p-trapped urinals are easily checked and there is no problem there. So what is left?
If there are floor drains in the rest rooms or elsewhere in the building (furnace room?), the traps down there may have dried out allowing gas to escape. Simply pour some mopping or disinfectant solution down each drain to refill the trap.
The vent stacks are easily seen above ... — Lynn E. Krafft
, ICAN/ATEX Editor