Q&A / 

Foul Odor From Shower and Sinks

HELLO TIM: I consider myself very handy around the house with everything from electrical to plumbing. However I feel like this problem is getting the best of me. The problem is we often (not everyday) have a very strong sewer odor that comes from the sink drain in our Master bath. It only occurs during the first use in the morning and seems to be emanating from the overflow hole entrance of the sink.

I have cleaned the drains (P-Traps) and do find residue from toothpaste and stuff but nothing that explains this. We do ever so often get the same smell from our walk-in shower too! I have heard that if the problem is a clogged vent pipe on the roof it will make a gurgling sound and also it would smell other than first time we use the sink of a morning. We never hear these gurgling sounds. If you have any suggestions I would appreciate it. We have black plastic pipes and the house is 4 years old, this started about 1 year ago. Thanks, Jim

DEAR JIM: I know exactly what the problem is. The odor is caused by bacteria that is breeding and multiplying in the bio-film that is coating the vertical drain pipe / tailpiece between the fixture trap and the actual drain outlet in the fixture. It is not the vent pipe unless you know for a fact the trap is being siphoned. The gurgling / suction noise is unmistakable and you have indicated you never hear it.

The reason you smell this when you first use a fixture is simple. The motion of the water first hitting the bio-film releases some of the bacteria molecules into the air.

Remove the drain strainer in the shower and I guarantee you will see a layer of slimy goo on the side of the pipe leading down to the trap. Clean off this goo. Do the same in the sink. You will have to remove the sink stopper to gain access to the vertical tailpiece.

The overflow tube that leads from the top of the sink to the tailpiece can also be a contributor to the problem. It is tougher to clean. I have had success using a turkey baster filled with a solution of Oxygen Bleach to kill the bacteria. You have to squirt the solution into the overflow tube vigorously several times and let it sit to try to coat the entire lining of the tube.

Message from Tim:

Years ago while researching a column about cleaning decks, I discovered the wonders of Oxygen Bleach. It is perhaps the 'greenest' cleaner I know of as it uses oxygen ions to break apart stains, dirt and odor molecules. There are no harsh chemicals, and it works on just about anything that is water washable.

I decided to create my own special blend using ingredients made in the USA. In fact, the raw materials in the active ingredient are food-grade quality registered with the FDA. I call my product Stain Solver. I urge you to use it to help with cleaning projects. You will be amazed at the results!

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4 Responses to Foul Odor From Shower and Sinks

  1. I have a similar issue with my kitchen sink. I never hear a gurgling and only need to use a little water. A lot of water doesn't seem to trigger it as bad. I have replaced the tailpiece from the bottoms of the drain baskets, to the outlet beyond the P trap. I am still having the problem though. Any more suggestions? after my P trap the drain drops at a 45 to where it drops vertical through the floor to the drain line. The vent through the roof connects about a foot to the left (and slightly uphill) and the drain (1 1/5" PVC) drops to the main outlet about 15' away.

    • Daren, your question requires lots of typing, plus I have some questions for you so I can give you the correct answer(s). I only do pithy answers here in the comment section. If you want to protect the investment you have in your house and not waste time or money *hoping* you make the right decision, you should talk to me on the phone for just 15 minutes. It'll be the best investment you've ever made in your home!

  2. Tim, old 1880 house. sewer smell coming from shower drain (trap is full of water). shower drain is 15 yrs old. just started noticing the smell 13 months ago. no plumber understand why. I do clean the drain cover and use a tooth brush to remove the black slime but still can't get rid of the smell. Help

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