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Not sure if this goes in plumbing

We have been having an issue when its really cold outside, with low water levels in toilets and a bad small coming from the laundry room sink (only when the low toilet level happens). The laundry room is on the main floor across from the main bathroom. We have a bungalow (built in 2010), and are on well and septic. Our tank was pumped summer 2012. The low water level in the toilet bowls is corrected with a flush but then sometime while we aren't watching it goes down again. I have noticed when I flush to fix the low level, there is a glugging noise in the laundry room sink pipes and the water splashes up from the toilet. I run water down the laundry room sink which fixes the smell for a bit. Could this be a venting issue or a septic issue? Thoughts?


Re: Not sure if this goes in plumbing

It sounds to me like your house is not vented. According to the Canadian plumbing code a septic tank must be vented by a four inch pipe going through the house and terminating all the way to the roof. Also all fixture must be vented to avoid negative and postive pressure. In your case when you flush the toilet it causes a negative pressure and sucks out the water in the p-traps near by. I would find out who did the plumbing and sue the guy. I do not know the american codes but they must be close to the same.

MLB Construction
Re: Not sure if this goes in plumbing

i semi agree with what bill said. i think he's correct about why the water is being pulled out of the bowl but i doubt that your plumbing system isn't vented. more likely the cause is a blocked or clogged vent. any plumber with a snake camera can do a little detective work and determine what's wrong.

Re: Not sure if this goes in plumbing

I agree. Your first step is to check your vent, and chances are that you have a vent. It could be semi blocked or undersized, and if that's the case, should be corrected.

Re: Not sure if this goes in plumbing

If this is in the US, chances are that it may still be under the builder's liability. Where I'm at, plumbing must be covered for 5 years save for fixtures and faucets. Call the builder and if they're no help, call your local Home-builder's Association and see what they have to say about how long the builder remains liable for plumbing.

I'm curious why you had the septic pumped with only 2 years use. Normally this is needed only at 6-10+ year intervals if it's sized properly. If that was done trying to cure slow drainage, I'll wager a weeks pay that something is wrong with the venting.


A. Spruce
Re: Not sure if this goes in plumbing

Sounds like a venting issue to me as well.

Re: Not sure if this goes in plumbing

I agree, too, that it's a venting problem. But you indicate that it only happens in very cold weather.

I suspect that there is a horizontal run of a vent pipe (possibly in the attic) that is not sloped correctly. As a result, rain water entering the roof vent collects in the pipe, blocking the free flow of air. During the summer months, with less rainfall, it dries out. In moderate temperatures, that water in the pipe is liquid and may allow it to 'gurgle' there instead of the traps under the sinks; in extremely cold weather it freezes and totally blocks airflow.

Repair may be as simple as properly supporting the pipe to maintain slope so that the water can drain down all the way to the septic.

Another possibility: the snow on your roof is higher than the vent pipe, and the top of the pipe is blocked with snow.

Re: Not sure if this goes in plumbing

It's possible the vent has frosted closed.

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