Advice please - toilet water level varies

Our house is about 10 YO and we have always had a problem with the second toilet (toilet 2 in the drawing attached).

Once or twice every few weeks, I find that the water level in toilet 2 has gone down and on occasions, it has gone down so far that sewer smell comes up. We rarely use this toilet.

I think it may have happened with toilet 1 on the odd occasion also.

My understanding is that the air relief pipe should be at the end of the run, ie. where the pipe leaves the house.

But our's is between the 2 toilets.

Do I need to employ a plumber to instal another air relief pipe? If so, where?

The drawing is not to scale.

Nothing wrong with vent position, however there is no pipe lengths or pipe sizes so its a little hard to tell. Could be the proximity of a branch drain to the junction for the toilet, the toilet looks to be a junction on its back on the main line. Could be a partial blockage somewhere.

Your cheapest, most efficient solution is to flush the toilet once a week, used or not.

The water is probably evaporating, or possibly escaping through a slow leak somewhere. If evaporation, there is nothing you can do about it. If a leak, and if it is so slow that you're only losing a cup or two per month, then it isn't worth pursuing.

Just flush occasionally.

I doubt that much water would evaporate in a few weeks, nor would the toilet be leaking to lose the water, it would be all over the floor!

Air pressure in the house causes it.

Have the same happen here and I tracked it down to having a door open that is facing into the wind and no other windows or doors open.

The wind increases the air pressure and pushes the water down in the bowl causing some to escape.

Stronger the wind, bigger the effect.

ps: yes I stood and watched it happen...... Gee I have a lot to do....:doh:

wonderplumb, I'm guessing you are a plumber, so you definitely know a lot more than me. I definitely won't debate with an expert :)

That said, I've had a situation like this before. Both downstairs toilets used to go dry if you were away from the house for more than 2-3 weeks. I've heard of similar problems from estate agents trying to sell empty houses ... unless someone flushes the toilets occasionally, there is a chance the bend will dry out.

Can't be sure of the cause, but the remedy I've always heard is to flush the toilet occasionally.

Of course they do dry out, as does the floor waste and sink traps etc, but I think its more sinister than that. With the air pressure thing its more in the vent pipe itself than in the house, a wind blowing across the vent pipe, which can be affected by the proximity of a pitched roof will cause pressure fluctuations and if not vented correctly will cause a fixture to suck its seal. Mostly found in boundary trap areas though.

A couple of questions?

Does the loss in water seal happen around the same time as the laundry is used?

Do you ever hear gurguling sounds from that toilet?

Does the toilet flush ok or does the water rise up alittle in the pan first.?

PS over here in S.A. the vent needs to go between the last two fixtures so therefore yours would be on the wrong side of the ensuite run.
Im reasonably sure that this is the rule for all of australia?

Not quite, they say the last two fixtures only because you require at least one fixture running past the vent so the vent doesnt block in the event of a choke. The rule is you cant have any more tham 10m of unvented drain, so as long as those fixtures are within 10m of the vent they are OK, however the LT point and the BSN drain seem a bit suss.

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Originally Posted by wonderplumb

Nothing wrong with vent position, however there is no pipe lengths or pipe sizes so its a little hard to tell. Could be the proximity of a branch drain to the junction for the toilet, the toilet looks to be a junction on its back on the main line Yes, the toilet pipes are perpendicular and go straight into the main. Could be a partial blockage somewhere.

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Thanks for the prompt responses.

I have used a plan of the house to estimate the pipe lengths and have added the pipe diameters.

I don't think it is due to evaporation or when the laundry tub is drained, it seems to happen at random. But I'll keep these possibilities in mind.

I assume it is not a partial blockage as (as far as I can remember) it has been happening since the house was built 10 years ago.

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Originally Posted by bricks

A couple of questions?

Does the loss in water seal happen around the same time as the laundry is used? No, seems to be at random

Do you ever hear gurguling sounds from that toilet? No

Does the toilet flush ok or does the water rise up alittle in the pan first.? It flushes normally

PS over here in S.A. the vent needs to go between the last two fixtures so therefore yours would be on the wrong side of the ensuite run.
Im reasonably sure that this is the rule for all of australia?

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Thanks for the response, answers above.

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Originally Posted by wonderplumb

Of course they do dry out, as does the floor waste and sink traps etc, but I think its more sinister than that. With the air pressure thing its more in the vent pipe itself than in the house, a wind blowing across the vent pipe, which can be affected by the proximity of a pitched roof See below will cause pressure fluctuations and if not vented correctly will cause a fixture to suck its seal. Mostly found in boundary trap areas though.

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The roof has a 30 degree pitch and the vent pipe is about 200 mm long after coming through the tiles.

Every thing seems OK except for, the hand basin line to toilet 1 is a bit far for 40mm and reduced too close to the toilet, shower to toilet 1 seems to take off too close to the toilet point, the bathroom group on the downstream side of toilet 2 is sized incorrectly, it should be atleast 65mm from where it picks up the bath. This is based on the info you've given me though, assuming the sizing and measurements are correct, as far as venting goes there is nothing wrong with the way its installed. Is there a possibility the vent may be blocked? Birds nest or something? The cowl hasnt been broken in a storm allowing birds in there? Just a few more possibilities. Do you know if your in a boundary trap area or not?
Though not really relevant where is your floor waste's and your surcharge gully?

Quote:

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Originally Posted by wonderplumb

Every thing seems OK except for, the hand basin line to toilet 1 is a bit far for 40mm and reduced too close to the toilet, shower to toilet 1 seems to take off too close to the toilet point, the bathroom group on the downstream side of toilet 2 is sized incorrectly, it should be atleast 65mm from where it picks up the bath. I'll go under the house and check on these points. It was done by a brief visual inspection & looking at the house plan. I assumed that the 50 mm pipes are 50, they may be 65. I'll check. This is based on the info you've given me though, assuming the sizing and measurements are correct, as far as venting goes there is nothing wrong with the way its installed. Is there a possibility the vent may be blocked? I'll push a hose down it to check. Birds nest or something? The cowl hasnt been broken in a storm allowing birds in there? No the cowl is OK. Just a few more possibilities. Do you know if your in a boundary trap area or not? I don't know what a boundary trap area is.
Though not really relevant where is your floor waste's and your surcharge gully?

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Thanks for the response. I don't know what you mean by "floor waste's and your surcharge gully".

A boundary trap is your shaft at the boundary before the drain enters the sewer main. If it is a boundary trap it will basically be an 'S' bend at the bottom that holds water, accompanied by a tin looking vent next to it somewhere. If not it will be a straight shaft with no water in it and no vent. A floor waste is the floor drain in your bathroom, which can be connected to the sewer with a fixture running through it or dry, which will discharge outside the house with a flap over the end of it, most commonly 2". A surcharge gully is outside the house, usually at a low point, with a grate over it and holds water also. Usually about 3" above ground level and may or may not have a garden tap over it. This is what over flows when the sewer blocks up and stops the sewage coming up through your floor waste or your shower.

Quote:

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Originally Posted by wonderplumb

A boundary trap is your shaft at the boundary before the drain enters the sewer main. If it is a boundary trap it will basically be an 'S' bend at the bottom that holds water, accompanied by a tin looking vent next to it somewhere. If not it will be a straight shaft with no water in it and no vent. A floor waste is the floor drain in your bathroom, which can be connected to the sewer with a fixture running through it or dry, which will discharge outside the house with a flap over the end of it, most commonly 2". A surcharge gully is outside the house, usually at a low point, with a grate over it and holds water also. Usually about 3" above ground level and may or may not have a garden tap over it. This is what over flows when the sewer blocks up and stops the sewage coming up through your floor waste or your shower.

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Thanks. No we don't have either a boundary trap, a floor waste drain or a surcharge gully.

I went under the floor and made some measurements. I also discovered that some of my assumptions were wrong. See the attachment.

The 50 mm pipes are definitely 50 mm, not 65.

Hey bloke been doing alittle research on your predicament.

Wonderplum hasn't told you anything I think is incorrect.

But I don't agree as a plumber with the position of that vent- I just doesn't look right to me.

For Wonderplumb I really think that the vent should go on the upstream side of the ensuite run.
This is due to Clause 3.9 (c) in your code book. Reffering to the upstream end of the drain, this drain drawing to me looks like its in the middle.

Although I'll say it now that this drain doesn't technically break any rules!

Would you agree that a good solution as far as cost might be concerned would be to cut in an AAV at the kitchen sink under the bench?

This would do two things

• There would then be a vent in an upstream position of the drain, removing the position of the vent as a possible cause.
• It would add and extra vent which wouldn't hurt as the fixture unit rating is quite high for a 50mm vent. ( still legal though)

Cost about $75 If done at home by handy man?

You also should check the falls on your drain, a 10mm spacer on the end of a 600mm level will give you the correct fall.


My hypothetical reaoning behind the problem is that the water from the kitchen sink, laundry trough and bath may be stalled at the last bend before exiting the building. This might be causing the pipe to fill up at this point, creating a suction every time a large flush occurs.

It's the only thing I can think of other than tree roots or an undergrade drain, Both of these are readily obvious seeing as the drain is visible.


See what wonder plumb says but for the cost associated with doing it, I think that you'd be foolish not to try adding an extra vent ( AAV) under the sink.

Bricks,
Thanks for those thoughts. I'll see what wonderplumb's opinion is.

I'll check the slope of the pipes at the next opportunity - next week as I've just had some physio on a leg problem.

What is an AAV?

Len

It's an Air admittamce valve, it only lets air into a pipe system. So you could cheaply cut one in under your sink and it won't let sewer smell get out and into your house but will let air into the drain system.

the vavle costs around $15-$30 plus some fittings.

It is basically like cutting in another vent pipe that you don't have to raise to above the roof level.

I do agree with Bricks, I personally would have put it on the upstream side of the ensuite before the kitchen sink, but as we well know thats in a perfect world and construction will get in the way of these things. Technically there is nothing wrong with the position though not really a good look. Mate an AAV would be a good place to start, I would be inclined to put one under both the KS and the ensuite basin to relieve that bathroom group a bit, but the kitchen sink would be a good place to start. I just had a flashback to a job a few years ago, where we put in caroma carravelle pans with the concealed waste and the seal was sucking out of one of the pans from day one. Popped it and found that the pan collar rubber had partially covered the waste of the pan, causing it to back up a little and then suck its seal. Just a thought. suprised i can still think after last night...............:(

P.S. bear in mind that your dergo vent iis installed 100mm above the wier of the trap, or as close as you can get it!

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Originally Posted by wonderplumb

P.S. bear in mind that your dergo vent its installed 100mm above the wier of the trap, or as close as you can get it!

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Thanks Bricks & Wonderplumb.

I assume the dergo vent is another name for an AAV.

I'm not sure what you mean by "its installed 100mm above the wier of the trap".

My interpretation is that it should be installed 100 mm above the water level in the sink (or ensuite basin) trap on the sewer side.

If this is correct, I don't see how it can be done since the water level will be at the bottom of the 90 degree bend that leads to the sewer. It is therefore not possible to install it 100 mm above this level.

Obviously I'm missing something.

you cut into the pipe lower than the trap, anywhere really- thats sraight section where you can easily spring in a junction.
Then extend the pipe using 45 degree bends ( 90's ok too) so that the pipe becomes another vertical riser. you then install the valve as high as you can get it in the kitchen cuboard.

This is not installed in-line but on a seperate pipe within the cuboard.

Thanks Bricks,
My understanding of what you wrote is as follows.

Cut the pipe and insert a 45 degree T (or would you call is a Y?) junction. Use a 45 degree bend to make the pipe vertical and install the valve on it as high as possible in the cupboard.

Is that correct?

correct. The T peice is a 50x50x45 degree pvc tee,

I normally put them right up about 20mm down from the underside of bench and right off in the back corner.

Thanks Bricks.

Sorry mate I should have explained it a little better but bricks has got you sorted, dergo is actually a brand of AAV, every one here just calls them dergo's because its less work!

I call them durgo's too wonderplumb, just that lately it seems that every plumbing store here in adelaide has lost all it's staff and hire new punk kids to run the shows. Ask them for a durgo and they type it into the computer and say "what's a durgo" coz apparently here in SA that brand is now hard to get or something.

Thats it mate, all the good blokes that Ive delt with at my suppliers have had a gutful of the politics (what politics I dont know, its not a very involved job) and gone to the commercial side of Hardly Normal. Now they got all these young fellas that couldnt give two f%&ks, eg. one store has this young fella that always looks stoned and gets the giggles when you ask for a nipple! Just before chrissy I went in to get some stock, inluding a few 1/2" nipples and he pulls the top of his shirt down and says, there mate thats about 1/2":no:. I do see the funny side but not when you have a store full of people! I think he's a bit suss. Sorry champ ranting again..........

Yeah i think studor make one and hepvo or hepworth make one

Yup studor are the one's I normally end up with. I know what you mean about stoners in the stores, They can't work out anything. I get alot of deliveries and these guys are true neanderthalls, if they havn't got it- they just substitute it with anyhting that looks close, gives me the s.... every day. I have to check every order as it comes in.

Thanks Bricks & Wonderplumb for the assistance, much appreciated.

I'll have to install the AAV under the kitchen sink as it has 50 mm pipe.

Do you think I need one in the ensuite also?

The handbasin in the ensuite has a 40 mm pipe, so I would have to insert a 40/50 adapter - assuming that the AAVs only come in 50 mm.

Go with the one under the sink first, see how you go after all this is a process of elimination, not a garaunteed fix. Depending on the brand of the aav it will have various ways to connect them, and usually have a bush or an adaptor to suit different pipe sizes. When you buy it, and your other fittings, open it up and see what you need to connect it to the pipe. The bloke at your supply shop should be able to help, maybe, pehaps.....................

Thanks mate, I'll buy one tomorrow.