Mystery Sewer Gas Smell
Lynne K. has a colonial home in North Easton, MA. She's at her wits end about a sewer gas smell in the home. Let her give you a full report:
"I bought my home, a colonial, in Dec. 2008. It was built in 2003. Before I moved in, I smelled a rotten egg odor in the half-bath, as you enter the house from the garage. It's also the laundry room.
Originally, I thought the smell was from the realtor who had gone to the bathroom and not turned the fan on. The day of the closing, the same thing happened. I realized soon after that it was not the Realtor at all. There was no washer installed at the time.
Once my new front-load washer arrived, I got the odor and the sewer department guy at the Town Hall told me the trap was dry and I should put a cup of water down the pipe after I do a load of laundry. I did this faithfully, and didn't have the smell for a while. Then, it returned.
I’ve had at least six plumbers here. None of them could find an issue. I’ve spent a great deal of money and still have no answer. One re-sealed the toilet in 2010, while another put a camera down the washer pipe to see if the trap was dry. It wasn't. Another cut the wall behind the washer and found nothing wrong.
Several times, I did an empty load wash with an Affresh tablet, and other times, I used bleach in the “clean Washer’ cycle with hot water. The smell still returned.
A year ago, a new plumber came in, looked in the attic, said all was fine, and then re-sealed all the connections around the PVC pipes in the basement, in case that was the issue. I didn't have the smell for eleven months.
A month ago, I had a new power vented hot water heater put in. Instead of emptying the old tank's water outside, with a hose, the plumber undid the cover to the main pipe in the basement, coming from the septic tank, and emptied the water into it. A week later, the smell returned on a Sunday, when it was snowing. It also smelled in the basement. The odor was very strong. The plumber said it was methane.
He returned, undid the cover to the waste pipe and re-sealed it again. A day later, while it was raining, the smell returned. I called the Gas Company and the service man said it was not gas, but couldn’t put his finger on the problem.
The septic tank was pumped last April. I called another plumber who said to put mint oil down the stack. A septic guy said I need a fan on the roof because I was getting a down / back draft. Someone else said I need to do a smoke test to see where the smoke comes out of the walls to indicate a broken pipe/ vent. (I checked & it's $650 for that test. If I'm sure it'll remedy the situation, I'll do it, but I hate to waste that money.) Another person said to put a snake down the stack pipe. A second septic guy said it wasn’t the septic, but the flex pipe that moved under the sink.
I checked with the Town water foreman to see if it was the water. He said it’s not the water because it would smell when I run the hot water. It does not.
I've read lots about the rotten egg / sewer odor on-line. Is this odor harmful to me? I usually open the window to let the smell out. It does dissipate, but then just returns once everything is closed back up. In the bathroom, it's hard to tell exactly where the smell is coming from.
My plumber came back a week and a half ago and changed the assembly in the toilet. I didn’t had the smell again until, Dec. 5. That time, the odor was only in the cellar. There was no smell in the half-bath. I go around flushing each toilet, running the water in the sinks so the traps won’t get dry.
Last Saturday, I covered the washing machine pipe up with duct tape for a few days and I had no smell. Then, I took it off, did laundry, and the smell came back faintly.
I had a PVC street 90 installed on the stack pipe on my roof. The smell was there faintly today. I put the duct tape back on the pipe.
Why is the odor in the half bath sometimes and in the basement other times?
The plumber now wants to install a Pro-vent (in-line, jiffy cap) to the washer pipe so the plastic accordion pipe from the washer can be sealed into the pipe and no air will come out.
I am at my wit’s end. I’ve tried to find a pattern as to when the smell occurs, but I just can’t.
I'd appreciate any help you can give me about what to do next so I can remedy this problem."
Lynne, I'm a master plumber and I live just north of you in central NH.
Here are the facts:
- you have a leak in your plumbing drain / vent line system
- the leak is not in a drain pipe that carries liquid waste or otherwise you see the leak in addition to the odor
- the leak can be verified with a simple air test that's done in new construction for a final plumbing inspection
- the source of the leak will be found with the smoke test
The sewer gas is only harmful to you if you inhale it for a long time in concentrated amounts.
Your facts lead me to think the source is the toilet in the half bath near the garage.
Even though you had a plumber put a new gasket on the toilet, that doesn't mean it was done correctly. Read my past column about toilet gaskets and the correct height of a toilet flange with respect to the finished floor.
The least expensive thing to do is to put a new wax ring on the toilet, but make sure it's RIGHT.
The odor source could be a trap that's sucked dry because of a clogged vent pipe or an improperly designed drain system.
I've seen this first hand at a friend's house. Each time his washing machine discharged its water, it would suck the trap in the kitchen sink dry because the kitchen sink was not vented properly.
Watch this video to see how Tim SOLVED a problem in minutes!
I can call you, often the same day, in an hour or less from when you place your order.
In 15 minutes, I can save you THOUSANDS of dollars and take your pain away.
FULL Money-Back GUARANTEE
You have NOTHING to lose except the money you'll gamble if you move forward without my advice.