Questions & answers on cures for sewer smells & odors in or around buildings.

This article series explains how to find and fix the source of sewer or septic smells & gas odors in or at buildings: common odor sources and how to find and fix them.

Q&A on Remedies for Sewer Odors by Plumbing or Septic Defects

These questions and answers about the cures for sewer gas odors or smells were posted originally

at SEWER GAS ODOR REMEDIES - be sure to return to the advice given there.

On 2017-04-19 by (mod) - Is it my responsibility to bear the cost of fixing backdraft smells ?

Carol,

I don't know. That sounds like I should give a two part "answer"

1. Who owns the property? Who's leasing? If leased what are the lease terms?

2. Is there a health or safety issue involved?

On 2017-04-19 by Carol

Is it my responsibility to bare the cost of backdraft smells from pipes when living on an easement

On 2016-12-24 by Fiona

Forgot to mention it's cold out and there lots of snow

We recently had the pipe that connects our home to our septic system replaced as there was a crack in the original pipe.

We had the septic tank pumped out at the same time. Everything in the house seems to be working as normal but when I'm outside near where the septic tank is I can smell sewage.

What would cause this? Would the pipe be leaking?

On 2016-07-31 by (mod) - pumping the septic tank doesn't fix a drain odor

No, Karen. Pumping the septic tank won't fix a problem that appears at specific plumbing fixtures nor would it fix a problem that is causing septic tank backup, abnormally high sewage levels in the tank, clogged drain lines, nor a failing drainfield.

What pumping does is extend the drainfield life by reducing the flow of solids out of the septic tank into the soakaway beds.

Look first for inadequate venting or a clogged or broken vent line causing siphonage of water out of the plumbing trap
Then look for a loose toilet or bad wax ring seal

On 2016-07-31 15:56:44.355748 by Karen

I recently started to smell sewage coming from my toilet and sink in the bathroom. Could it be as simple as draining my septic tank?

On 2016-06-27 by (mod) - sewage odors blamed on downdraft from rooftop vents

Indeed, Tom, other readers have on occasion complained of sewage odors that they were pretty certain were coming from downdrafts from rooftop plumbing vents;

Some building sites combine terrain shape, tree locations, building shape, building and roof slope orientation, and prevailing wind direction to suffer unusual downdrafts.

I've suggested looking into a wind-operated rotating vent cap that is basically a 90 degree elbow that operates like a wind vane to aim the vent outlet away from oncoming wind; the cap / elbow must not close off the vent but it can both aim it away from wind direction and avoid downdrafts that can also push air backwards into the vent system.

Keep us posted; what you find may help others.

On 2016-06-27 by Tom

I recently had a custom home built. It includes a septic system. We have a significant sewer gas smell outside of the house. The gas smell is coming from the house plumbing vents on the roof. The smell seems to be blowing from the vents, down to the ground level.

My builder has increased the size of the vents to 3", he has also increased the height of the vents to roughly 6" above the roof ridge line.

We have smoke tested the vent system and everything looks to be working as designed.

It is important to note that the clean out between the septic tanks and the house is not a source of smell. Have you dealt with this type of issue before?

On 2016-06-07 by (mod) - smell doesn't appear until building is occupied

Occupants use toilets, wash stuff in sinks, move things, turn things on and off, open and close windows, turn fans on or off, or do other things that change the use of gas appliances and the movement of air and thus odor transport in buildings.

A common experience is an increase in sewer gas odors when water is run down slow, partially-blocked, or poorly-vented drains.

On 2016-06-07 by Anonymous

Thanks for your reply. What does the fact that the smell didn't occur till after the place was occupied hint at? If anything?

On 2016-06-06 21:56:46.982549 by (mod) -

Unfortunately there can be other harder-to spot sewer gas leaks including a drain line broken in a wall or under a floor or a vent pipe that is incomplete or mis-routed or not properly jointed.

On 2016-06-06 by JennyN

My daughter recently bought a small house that had been vacant for several months. 2 or 3 days after she moved in we started to notice a sewer gas smell.

We ran water at all locations to make sure that the traps hadn't dried out and poured water down the basement floor drain.

When she first looked at the house (several times before buying) there was no odor, but the water had not been turned on yet. It wasn't until a couple of days after the water was turned back on she was living there that the problem started.

On 2016-04-04 by (mod) - diagnosing sink trap odors

Dwight

The fact that you only notice the smell at first use suggests that water right in the sink trap is becoming smelly overnight, is being stirred up when the sink is used, and then emitting gases. But here are some more thoughts.

I'd try

1. tape over the sink overflow and see if the smell stops (it may not completely depending on how the sink is constructed, but it should)

2. check that the sink tailpiece and trap are correctly installed, and look from below to be sure there are not other openings that shouldn't be there - cracks, casting errors &c.

Openings in the upper tailpiece or sink drain fitting will indeed connect the sink drain opening to the sink overflow vent - after all, water overflowing through that vent has to be able to flow down in the sink shell and into the drain: I suspect that's the odor path.

If that's the odor path there may be a design oddity about this particular sink that makes it stinky.

Another possibility is that the sink is not properly vented or that the drain is partly blocked: conditions that can cause siphoning of the water from the sink trap. If water is siphoned from the trap odors can pass up both through the drain opening and through the sink vent.

I suppose another possiblity is a sink drain design that I've not seen (such as double-trapping) that maintains the water in the P-trap but somehow permits gases from below the P-trap to pass around into the sink shell and out through the sink overflow vent.

An analogue to this problem occurs at double-sinks with individual traps but sharing a common drain: if one trap for any reason is dry the other sink may not smell but the dry trap may still pass on sewer gases.

On 2016-04-04 20:08:16.224281 by Dwight Cutting

Now that you mention it I do believe the smell may be coming from the overflow drain opening in the sink. The smell is in no there room. The kitchen or the downstairs basement washroom. The smell only comes from this sink,and just first thing in the morning after you turn the water on.

On 2016-04-03 15:52:33.624552 by (mod) - odors at the kitchen sink

Dwight, I'm not sure what's happening either.

Is the drain slow?
Is there gurgling at this or other fixtures while the fixture is draining?

Are we sure the odor is from the trap and not the water source?
Could odors be coming out of the sink overflow drain opening in the sink bowl? (Sniff there)

I'm wondering if this is peculiar to this particular fixture - smelly trap contents venting out of its overflow.

On 2016-04-03 by Dwight Cutting

We recently had our kitchen sink snaked by a plumber. We then installed a new sink in the main floor bathroom and cleaned out that drain and installed a new P-trap. Recently first thing in the morning when you turn the water on in the bathroom sink and let it run you get a sewer gas smell.

The p-trap is not drying out and you don't get the smell till the water is turned on. I cannot figure out why it does this.

I am trying to hold off bringing in a pro and hoping I can fix it myself. You only get the smell first thing and not the rest of the day.Any ideas

On 2016-02-13 by (mod) - persistent sewer odors at toilet

J I suspect that either some cleaning and disinfecting of the damaged floor was not extensive enough or the new wax ring is not sealed properly.

On 2016-02-12 by J

My toilet was loose so since I am disabled and recently widowed I let a friend of my late husband's remove the ceramic tile to what I thought was to replace the wax o ring.

After removing the toilet we found there had been a water leak below the toilet.

After replacing the water line, replacing the wood holding the toilet,replacing the o ring and placing the toilet 3 days ago, I'm still smelling sewer gas smell.

We have a septic tank so, I usually pour rid-x down it once a month with no problems. I poured another box down yesterday afternoon but, did nothing to help the smell. Until the removal of the toilet I didn't have this problem.

I get a headache soon after I return from the store and my lungs are starting to feel strange. What should I do??

...

Continue reading at SEWER GAS ODOR REMEDIES or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Septic & Sewer Odor Articles

• SEPTIC SYSTEM ODORS - home
• SEWAGE PUMP ODORS
• SEWER GAS ODORS - home
• SEPTIC / SEWER ODOR SOURCE TABLE
• SEWAGE ODOR SOURCE LOCATION
• SEWER GAS ODORS in COLD / WET WEATHER
• SEWER GAS ODOR REMEDIES
• SEWER GAS ODOR SOURCE TEST FAQs
• SEWER LINE REPLACEMENT
• SEWER / SEPTIC PIPE CAMERAS
• SEWER SEPTIC GAS CONDUIT LEAKS
• SEWER SEPTIC ODORS in HVAC DUCTS
• SITE WEATHER or NEIGHBOR'S SEWER ODORS
• TESTS for SEWER GAS INDOORS
• TRACK SEPTIC ODORS to SOURCE
• TRACK SEWER ODOR by WEATHER
• TRAP SIPHONAGE & SEWER GAS
• WATER POLLUTANT SOURCES
• WET WEATHER SEWER ODORS

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