Home>Discussions>PLUMBING>Basement Drain Smells - Done the obvious things?
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dan_vella
Basement Drain Smells - Done the obvious things?

1957 house, we have been living for 4 months. In the past week the floor drain in our utility room has intermittently been emitting a sewer smell. I have looked around for causes so far I have:

1) Poured (gallons) water into the drain to ensure it is not dry and not blocked/backed up.
2) Gone up to the vent on the roof to check for obstruction - none visible

Shortly after we moved in I had the main drain inspected by video, saw with my own eyes that everything was in great shape down there - so this combined with 1) makes me think a backup is not the issue.

The smell from the drain has more or less coincided with the spring thaw (Toronto), of what has been a colder than average winter and one with a good amount of snow accumulation. Most of the snow is now melted.

Looking in the drain I can appear to see the top of the opening where the water flows out, this suggests that there is a pathway for the sewer gas to escape. To test this I put a round piece of rubber in the drain so that it is still functional but so that it covers the gap between the water level and the top of the opening. This seemed to do the trick.

My concern is that why is this happening now - I am assuming that the opening has been there the whole time and something has caused the smell to reach the house. Could it be that the thaw has risen the level in the city drains and pushed the gases to the drain?

I want to be sure that I am treating the cause and not just the symptom of a bigger problem. Grateful for any thoughts/experience.

ed21
Re: Basement Drain Smells - Done the obvious things?

Try pouring in slowly just enough water to close the opening. The water could be siphoning out when you pour in the gallons of water which would make me think there is a venting issue. Clogged vents aren't always visible from outside.
Does the drain go to the sanitary line or a sump?
It's also possible that some settlement has caused a problem.

dan_vella
Re: Basement Drain Smells - Done the obvious things?
ed21 wrote:

Try pouring in slowly just enough water to close the opening. The water could be siphoning out when you pour in the gallons of water which would make me think there is a venting issue. Clogged vents aren't always visible from outside.
Does the drain go to the sanitary line or a sump?
It's also possible that some settlement has caused a problem.

Thank you for responding. I agree that, so far, a lot of this points to a venting issue. What causes me to doubt is that all the drains upstairs are draining fine, wouldn't this impact the whole house?

We do have a bathroom in the basement - the toilet and shower gurgle when draining, I can't tell if they are vented properly, could use of these be drawing water out of the drain?

I am still at a loss as to why this happens all of a sudden.

Thanks again

dan_vella
Re: Basement Drain Smells - Done the obvious things?
ed21 wrote:

Try pouring in slowly just enough water to close the opening. The water could be siphoning out when you pour in the gallons of water which would make me think there is a venting issue. Clogged vents aren't always visible from outside.
Does the drain go to the sanitary line or a sump?
It's also possible that some settlement has caused a problem.

To your question - drain goes to sanitary line.

ed21
Re: Basement Drain Smells - Done the obvious things?
dan_vella wrote:

Thank you for responding. I agree that, so far, a lot of this points to a venting issue. What causes me to doubt is that all the drains upstairs are draining fine, wouldn't this impact the whole house?

We do have a bathroom in the basement - the toilet and shower gurgle when draining, I can't tell if they are vented properly, could use of these be drawing water out of the drain?

I am still at a loss as to why this happens all of a sudden.

Thanks again

Yes to the other fixtures drawing the water out of the drain. The vent is likely partially blocked and when the other fixtures are used the floor drain is being used as the vent.

bill
Re: Basement Drain Smells - Done the obvious things?

A photo would answer a lot of questions

dj1
Re: Basement Drain Smells - Done the obvious things?

The cause is most likely a dry trap. You need to install a primer device, it automatically injects water into the trap when dry.

This device is code in my city.

How to do it depends on your situation and budget.

dan_vella
Re: Basement Drain Smells - Done the obvious things?

UPDATE

Last night I saw what appeared to be toilet paper in the the floor drain and waste matter. Because of this I have had a plumber come out and have a look, am concerned about a back up.

He said that the exposed opening, because it faces away from the front of the house, is probably coming from the weeping tile - what I don't understand is why the smell would come from the weeping tile.

What I also don't understand is how it is possible to get paper and matter backing up to the floor drain, yet when I pour water it the level barely moves - why isn't the drain being overwhelmed.

His suggestion was to break the floor to replace the floor drain, and while at it to get the camera down the length of the drain where he suspects there is a partial blockage - which would also explain the sluggish flush in the basement.

Trying to make sure this stacks up before I commit to the work.

dj1
Re: Basement Drain Smells - Done the obvious things?
dan_vella wrote:

UPDATE

Last night I saw what appeared to be toilet paper in the the floor drain and waste matter. Because of this I have had a plumber come out and have a look, am concerned about a back up.

He said that the exposed opening, because it faces away from the front of the house, is probably coming from the weeping tile - what I don't understand is why the smell would come from the weeping tile.

What I also don't understand is how it is possible to get paper and matter backing up to the floor drain, yet when I pour water it the level barely moves - why isn't the drain being overwhelmed.

His suggestion was to break the floor to replace the floor drain, and while at it to get the camera down the length of the drain where he suspects there is a partial blockage - which would also explain the sluggish flush in the basement.

Trying to make sure this stacks up before I commit to the work.

It's good that you have one plumber's opinion now, to give you some direction, but you need a second opinion.

In any event, you need a cam inspection for sure.

ed21
Re: Basement Drain Smells - Done the obvious things?

It still sounds like a venting issue to me, although a blockage could be the cause. It could even be a bit of both somehow.
Since it started recently something has happened rather than a poor design, although a poor design is more easily overcome by a problem.
I would scope the system before I started tearing the slab up.
Houses as old as yours often have issues with sanitary lines deteriorating, shifting and settling not to mention roots growing into the terra cotta pipe.
Where I am trap primers are only required in commercial construction.
A second or third opinion from a plumber is a good idea.

dan_vella
Re: Basement Drain Smells - Done the obvious things?

Thank for all the posts. I got a second opinion, glad I did - the first plumber would have replaced the floor drain and it would not have solved the issue, cowboy.

I got a cam down there and there is indeed a blockage, 125ft out so on city property. Now commences the City of Toronto merry-go-round.

The block seems quite bad, but it is draining. The distance of the block and the draining explains how we have got away with out any overflowing - I think we came pretty close though.

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