Another question about reduced water in toilet U bends?

Question

I have 3 toilets (loos) in my house, 2 upstairs and 1 downstairs. The water level in the toilet bowl in ONE of the upstairs toliets has been significantly dropping between flushes for the last month - it never used to do this and none of the others is doing it.

I looked and found a previous answer which said this is caused by the wind blowing over the stench pipe up the side of the house and creating a 'venturi' effect. This 'suction' air pressure sips a little water over the U bend in the toilet pan, which goes down the waste pipe. Hence, less water until the loo is flushed. Another previous answer said this would affect all toilets connected to the waste system. All of mine feed into the same sewer and we only have one stench pipe.

So - my question is - why is this only happening with one of the toilets and should I call in a plumber ???

Thanks for your time if you are able to help.

Answer 1

I am not buying into the venturi effect, because the toilet would have always done it. mathematically it can happen, but in actuality it doesn't. I think you are experiencing one or more problems. 1. vent pipe near toilet is plugged causing it to suck more water from the toilet bowl (trying to get air) 2. You have a wick action cause by something (piece of cloth, tampon, etc. )caught on the back edge of the "U" 3. you have a crack in the toilet bowl (could be internal) draining water into the drain. I would replace the toilet, or swap it with one of the others (to see if the problem follows the toilet) if you don't want to waste money on a new one

Answer 2

What is happening is this. Because you have 3 toilets all using the same waste pipe the e flushing of the others is syphoning the water from the toilet bowl. To overcome this, you have to have a anti syphon pipe fitted into the wate pipe which all the toilets run into. This is a plumbers job'. you will see anti syphon pipes fitted wherever there is a number of toilets.In old buildings you can see them on the outside walls.

Answer 3

First thing is to fix all leaking faucets and shower heads. This can waste a ton of water every year. Next you can install low flow shower heads and aerating faucets. These faucets add air into the flow so that you will receive the same pressure with much less water. Also turn off the water when you are brushing your teeth. Use it to wet and rinse the brush, but don't leave it running while brushing. If you can afford a new dishwasher, get one. Dishwashers are much more efficient at using water than washing by hand. Also make sure the dishwasher is full before running it.

Answer 4

It is happening to the upstairs toilet because it is closest to the vent on the roof. Also, the vent stack isn't one continuous tube...it is a series of connections into that one vent tube. The lower toilets won't have the problem because it takes much more "suction" to cause the venturi effect on the bottom toilets.

Answer 5

Try flushing it with hot soapy water if something has got caught it will soak the water away the hot water should shift it. It's worth a try before you spend any money.

Answer 6

maybe a cracked toilet or a bad wax ring leaking to lower the level

Answer 7

replace the flapper in the tank

Answer 8

YOU DEFINITELY NEED ANOTHER VENT PIPE FOR THE ONE THAT'S HAVING COMPLICATIONS.

Answer 9

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