Toilet bowl water - where has it gone?

Toilet bowl water - where has it gone?

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Corvid-2020

Original Poster:

1,994 posts

78 months

Tuesday 1st December 2020
quotequote all
Came downstairs this morn and went to use the toilet in the utility room and noticed that the water in the bowl was, well not there! There is a lute on the drain soby natural draining at least 4" of water should have been waterlocked.

I'd have been the last person to use the loo last night and the "bloo loo" bowl water was present then.

Haven't flushed to refill as if there is a leak I don't want to add to it. Visible floor appears dry. Floor is Italian marble over chipboard with a void underneath to ground at a guess.

Soil pipe goes straight under floor outside to drain manhole. No other connections into soil pipe, room is ground floor.

First heavy frost last night anything to do with it?

Black_S3

2,667 posts

187 months

Tuesday 1st December 2020
quotequote all
No aav or knackered aav?

Corvid-2020

Original Poster:

1,994 posts

78 months

Tuesday 1st December 2020
quotequote all
No, soil stack looks to just have a curved wire grill / mesh over the top rather than a valve. (Tis a rather dodgy plumbed house). Upstairs toilet on same stack is fine.

MattyD803

1,684 posts

64 months

Tuesday 1st December 2020
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Black_S3 said:
No aav or knackered aav?
If no immediate leaks around the toilet bowl visible (i.e. caused by a crack), then yep my thoughts also would be related to an AAV.

If you don't have one, or if like my cloakroom the toilet is "end of line", then perhaps something unusual is going on downstream in the foul water system causing suction to pull the bowl water through. We used to have this in our house in London where the sewers would regularly block and cause this sort of thing.

Might be worth asking your neighbours if they have similar set up in their houses?


Bikesalot

1,833 posts

157 months

Tuesday 1st December 2020
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Flush it....i'm intrigued

blueg33

35,533 posts

223 months

Tuesday 1st December 2020
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Blockage somewhere can have this effect - causes water to be sucked out of the trap

If the plumbing vent pipe is clogged with debris, it could choke the system. For example, when water is running down a waste pipe behind the toilet, that water is grabbing for air, and it could suck water out of the toilet bowl.

guindilias

5,245 posts

119 months

Tuesday 1st December 2020
quotequote all
I had exactly the same at my cabin over a cold winter - the water froze, cracked the u-bend bit and the water drained out through it onto the floor underneath (covered by the rest of the toilet). We chuck a load of salt in it now before locking up for the winter, but that's probably not practical for you to do every time the temperature dips!

Corvid-2020

Original Poster:

1,994 posts

78 months

Tuesday 1st December 2020
quotequote all
Flushed. Water back.

Seems to be at normal level, fortunately "household cleaning regime" means there is a historical level marked I can check against.

The outside drains are "common". I'd just be surprised that enough of a vacuum could be pulled by some event in the drain, whilst remaining waterlocked, though we are the last house before the common drain hits to road so could be possible, but wouldn't that have pulled on teh seal on the upstairs loo as well?

Hoofy

76,253 posts

281 months

Tuesday 1st December 2020
quotequote all
Does your dog have a blue mouth?

rallye101

1,865 posts

196 months

Tuesday 1st December 2020
quotequote all
Probably rats!

Corvid-2020

Original Poster:

1,994 posts

78 months

Tuesday 1st December 2020
quotequote all
Was about to edit post further up, realised you'd need more vac (~0.3 bara) to pull the upstair lute free of water, but a small event could be enough to pull the downstairs loo.

No dog, but the cats litter tray is being monitored to see if the litter turns blue.

Wifes friend has just texted her to say "definitely rats". I decided to agree and told her she better not sit down on teh loo in case a rats bites her bum! Funny watching her pee standing up al la the scene in the Full Monty.

So the toilet lid is down and a pan of hot water next to it "for when the rats come knocking"....

.....going to be a fun paranoid few days.

TwistingMyMelon

6,385 posts

204 months

Tuesday 1st December 2020
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Checked your drains for flushing/blockages would be my first point of call

MattyD803

1,684 posts

64 months

Tuesday 1st December 2020
quotequote all
Corvid-2020 said:
Flushed. Water back.

Seems to be at normal level, fortunately "household cleaning regime" means there is a historical level marked I can check against.

The outside drains are "common". I'd just be surprised that enough of a vacuum could be pulled by some event in the drain, whilst remaining waterlocked, though we are the last house before the common drain hits to road so could be possible, but wouldn't that have pulled on teh seal on the upstairs loo as well?
You'd be surprised about the air volumes and pressures (+ve and -ve) that are moved/created within a public sewer system....especially when a few hundred/thousand litres of piss, crap and detritus are moving past your house along a 100mm pipe - the analogy would be "like a tube train through a tunnel". Especially where a minor blockage has caused a build up and the "slug" gets moving

As for your upstairs toilet, because the Soil Vent Pipe / stack is vented to atmosphere, any suction created in the mains gets pull in through the vent hence relieving any pressure seen by any toilets upstairs. However, it is likely your downstairs toilet is directly connected into the foul water sewer, and hence there is no opportunity of equalising or even partially relieving the vacuum. Your downstairs toilet bowl acted as part of the air admittance in this instance, taking your lovely blue water with it.

If it reoccurs, I would get onto your local water board to get a call in and speak to the neighbours - it could be developing into an issue.

MJNewton

1,728 posts

88 months

Tuesday 1st December 2020
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Was the bowl *completely* dry? If so, no amount of drain pressure issues would explain that as the bowl invert can't be cleared once the airlock has been broken.

TimmyMallett

2,810 posts

111 months

Tuesday 1st December 2020
quotequote all
Hoofy said:
Does your dog have a blue mouth?
Came here for this. Was not disappointed.

devnull

3,745 posts

156 months

Tuesday 1st December 2020
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In a previous home, I often found that if we had high winds, then the would be little to no water in the bog bowl in the morning.

eps

6,271 posts

268 months

Tuesday 1st December 2020
quotequote all
TimmyMallett said:
Hoofy said:
Does your dog have a blue mouth?
Came here for this. Was not disappointed.
Does the OP have a blue mouth? and had a dream about drinking cocktails last night??

TimmyMallett

2,810 posts

111 months

Tuesday 1st December 2020
quotequote all
devnull said:
In a previous home, I often found that if we had high winds, then the would be little to no water in the bog bowl in the morning.
Maybe too much information.

Hoofy

76,253 posts

281 months

Tuesday 1st December 2020
quotequote all
eps said:
TimmyMallett said:
Hoofy said:
Does your dog have a blue mouth?
Came here for this. Was not disappointed.
Does the OP have a blue mouth? and had a dream about drinking cocktails last night??
biggrin

rxe

6,700 posts

102 months

Tuesday 1st December 2020
quotequote all
While the idea of the dog slurping it up is highly amusing (we have a water bowl in the bathroom to avoid this...), it is more likely due to capillary action and a piece of bog paper.

You can try an experiment in the kitchen sink. Get a pan full of water, and drape a wet dishcloth over one of the walls, so that one end of the dishcloth is at the bottom of the pan, and the other end touching the bottom of the sink. Leave it overnight .... and lo, the pan will be magically empty.

In your bog, a piece of paper has got as far as the ubend and is draped over it. Capillary action pulls the water over the ubend and down the drain. When you flush it, the paper vanishes, and it was clearly caused by magic/your dog/you after a particularly spicy kebab.