Toilet blows bubbles

**John Kogel** · 05-18-2011, 06:16 AM

This is new construction, a basement suite is a couple of feet below grade. There are two sump pits in the back patio, But I think they are just for ground water. There is one 2" vent stack in the attic above this end of the house. There is a 3" vent in the other end of the attic, three more bathrooms.
Downstairs, it's a 3 piece bath and a kitchen sink, separated by a stairway. When I drain a few inches of water out of the tub, air bubbles blow out of the adjacent toilet.
Could this happen if there is a plumbing vent connected anywhere within 10' of the bathroom?

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**Eric Barker** · 05-19-2011, 07:12 AM

Originally Posted by John Kogel

Could this happen if there is a plumbing vent connected anywhere within 10' of the bathroom?

I don't see where that would make a difference.

**John Kogel** · 05-19-2011, 10:00 AM

Originally Posted by Eric Barker

I don't see where that would make a difference.

So what would make a difference then?

Ted Menelly · 05-19-2011, 11:33 AM

Originally Posted by John Kogel

This is new construction, a basement suite is a couple of feet below grade. There are two sump pits in the back patio, But I think they are just for ground water. There is one 2" vent stack in the attic above this end of the house. There is a 3" vent in the other end of the attic, three more bathrooms.
Downstairs, it's a 3 piece bath and a kitchen sink, separated by a stairway. When I drain a few inches of water out of the tub, air bubbles blow out of the adjacent toilet.
Could this happen if there is a plumbing vent connected anywhere within 10' of the bathroom?

Venting is the key. The bubbles are a clear sign of improper venting. As far as how much venting I would assume that a kitchen sink, toilet, bathroom sink etc would require a 3 inch vent. I would venture to say that the tub does not have a vent within 5 feet or so and the drain is connected just before the toilet drain wrong. Anyway it is all venting. What may cure it is a studor vent for the tub but not knowing the layout or distances they should do what needs to be done anyway. Call a plumber to figure the mess out or just write it up in need of repair and let the builder sort it out. If it is a new home the builder will just call the plumber to fix it anyway.

**Ken Rowe** · 05-19-2011, 11:38 AM

New construction...the builder never removed the caps from the plumbing vents on the roof. They normally aren't removed around here until the buyer takes possession, but most of time the builder forgets.

**Eric Barker** · 05-19-2011, 11:43 AM

If air is pushing up through the toilet then there's air pressure somewhere in the waste line that is not able to vent up through the soil stack. Trying to figure out what's causing it is way beyond my ability. I would however be interested in what a QUALIFIED plumber found out. I have seen (during inspections) where air pushes up through the toilet just before a geyser of really nasty waste water explodes into the room. My advice in those situations - run like hell.

Ted Menelly · 05-19-2011, 12:06 PM

Originally Posted by Ken Rowe

New construction...the builder never removed the caps from the plumbing vents on the roof. They normally aren't removed around here until the buyer takes possession, but most of time the builder forgets.

That is actually a very good reason as the air has no wear to go but either down the drain or up thru something else, like a toilet.

**John Kogel** · 05-19-2011, 06:12 PM

Originally Posted by Ken Rowe

New construction...the builder never removed the caps from the plumbing vents on the roof. They normally aren't removed around here until the buyer takes possession, but most of time the builder forgets.

No that ain't it this time. This is the only vent anywhere near that toilet.

Yes, I just said fix the bad vent. Now I'm concerned for my somewhat gullible client, (sorry, V..

).

**John Kogel** · 05-21-2011, 07:19 AM

Originally Posted by Ted Menelly

Venting is the key. The bubbles are a clear sign of improper venting. ... or just write it up in need of repair and let the builder sort it out. If it is a new home the builder will just call the plumber to fix it anyway.

I suspect 'builder' and 'plumber' are one-and-the-same dude.

James Duffin · 05-21-2011, 10:03 AM

What I normally see when there is a venting problem that involves a toilet is the water in the toilet bowl with be sucked out of the bowl by the siphoning action in the sealed drainage system. Did the toilets flush OK or were they sluggish?

**John Kogel** · 05-21-2011, 11:40 AM

Originally Posted by James Duffin

What I normally see when there is a venting problem that involves a toilet is the water in the toilet bowl with be sucked out of the bowl by the siphoning action in the sealed drainage system. Did the toilets flush OK or were they sluggish?

Just the one toilet downstairs, flushed ok, but I didn't try it with a floater.

Air blew out thru the toilet when I drained the tub.

James Duffin · 05-21-2011, 01:12 PM

Sounds more like a partially blocked sewer than a venting problem to me.

**John Kogel** · 05-26-2011, 01:26 PM

Originally Posted by James Duffin

Sounds more like a partially blocked sewer than a venting problem to me.

Thanks for that. However, blockage would be slowing the flush of the toilet too, no? Also, this is a new house, so no buildup of sludge, unless it's construction mud, or paper towels, maybe......

James Duffin · 05-26-2011, 02:16 PM

Originally Posted by John Kogel

Thanks for that. However, blockage would be slowing the flush of the toilet too, no? Also, this is a new house, so no buildup of sludge, unless it's construction mud, or paper towels, maybe......

The plumber may have psst somebody off and now there is a drink can in the 3" toilet drain.

Fred Herndon · 05-29-2011, 11:17 AM

Originally Posted by James Duffin

Sounds more like a partially blocked sewer than a venting problem to me.

Probably a few days late on this, but I had a similar situation this spring in a new home. My standard protocol for testing plumbing in new construction or houses that have been sitting empty for a while is to fill the sinks, plug the shower drain and at least partially fill the tub, then let the water go all at once while flushing the toilet. On this house everything worked fine downstairs, but when I got to the master bath the toilet bubbled back up, then went on down. When I flushed it again everythin seemed to work just fine - until the flooring installers walked in downstairs and started yelling about water coming out of the first floor toilet!

Long story short, it turned out that the sewer line was damaged at the tap under the street. It just took a lot of water down the drain for it to back up. Buyer got the new flooring he wanted, repairs (and new flooring) were paid for by the developer and the builder was just glad it happened before the buyers moved in. Client now gives my phone # to all his friends.