I purchased an existing restaurant a little over a year ago. I began noticing sewer smells coming from the dishwasher area, only after the dishwasher has been in use. All drains and floor drains run to a grease trap with is inside the unit that I rent. The problem only occurs when it is cold out, maybe 40F or colder. Apparently the problem has been ongoing for the last few winters. I believe that the odors are coming from a floor drain that the dishwasher pours into. That p-trap seems to be intact and is always filled with water. I do not think that the smell is coming form the grease trap since it is in a closet room that is kept shut by a door.

The grease trap is cleaned on a regular basis and I do use bacteria enzymes to help keep pipes from backing up. Recently we replaced a broken p-trap on a floor drain, which I thought might correct the problem but did not. I have also had the lines snaked and jetted, but that did not correct he problem either. All traps are filled with water and seem to be intact.

I am worried that I may have to dig up a bunch of pipe and/or have to replace the grease trap. Obviously this would be very expensive and I want to try everything possible before doing anything extreme. The building is 20 years old and is in decent shape. My neighbors on each side of me do not have this problem (it is in a strip mall so the neighbors are attached in the same building)

A friend of mine had a similar problem. He thought that there were broken pipes and that sewage was in the dirt below ground. He only had odor problems in the winter also, and thinks that it is the sewage in the dirt an that smells arise when the ground freezes. Does this sound right? He ended up selling before the problem was fixed.

The plumbers that I have had out for backups and to replace the one trap have not offered any advice other than saying that the p-traps should prevent this. They seem clueless. What do I need to do to find out what the problem is?

Any help would be greatly appreciated.

Thanks,
Kd1

Try to dump a gallon of bleach. Might work, but watch draining pipes. Let's see.

Some years back I had the same problem in a restaurant drain line.
" I believe that the odors are coming from a floor drain that the dishwasher pours into."
Restaurant dishwashers discharge large ammounts of grease that turns rancid and smells. I couldn't make any progress in eliminating the smell with a snake or chemicals until I rented a steam jenny and steamed out the lines. The steam melted the grease and made it liquid so that the crud on the pipe walls flowed out into the grease trap where it belonged. This was a "Hail Mary" last ditch attempt to stop the odor and whadda you know. It worked.
Good luck. Tom

Tom,

Thanks for the idea. Is there a specific kind of steam jenny for this job? I am wondering if you were able to run the end of the jenny down the drains through the p trap or if you just put the end of the jenny to the p, then let the steam run through the pipes.

Thanks
kd1