Why does my basin gurgle when toilet is blocked?

Jack C | March 01 2018 | KT6 6AF

When we have a lot of rainy weather my downstairs toilet tends to block up and can’t be used. (Upstairs toilet works fine.) The downstairs bathroom basin makes scary loud gurgling sounds especially when I flush the downstairs toilet. Is the toilet and basin somehow connected? If the rainy weather is the cause, wouldn’t that also block the upstairs toilet? I have tried plunging but this doesn’t work.


Comments (16)
March 08 2018

Sounds like the gully out side is blocked and the man hole may be effected as well


March 08 2018

Because it’s pulling air in when its flushed


March 08 2018

The basin waste pipe is going to be connected to the svp. The reason the basin gurgles is because there is a vacuum being caused when you flush the toilet because the svp is full because of the blockage you referred to. The gurgling is intact the vacuum trying to suck the water out of the waste trap on your basin. You could try an anti vac trap , these are available from most plumbers merchants


March 08 2018

Possible partial or complete blockage in manhole or svp


March 08 2018

call a plumber you are pulling a vacuum, the installation is wrong with no air vent!!!


March 08 2018

Manhole has blockage using sink as a air source. Needs rodding


March 08 2018

Your toilet waste pipe it's near the basin , just change the trap in your basin waste pipe. This is the link https://goo.gl/images/zXHJyC


March 09 2018

Most probably a blocked drain or very slow running drain causing the problem. This will cause the vacuum effect you are experiencing.


March 09 2018

Possibly blockage in the pipework


March 13 2018

the level difference between the main drain and the toilet? lack of venting to the main drain pipe forming compression inside the pipe? clogged drainage pipe or redimensioning of pipes or sloping slope made wrong? it is best to see the work forgiveness if not quite understood? I used google translator


March 13 2018

Just buy some one shot and pour it in the toilet


March 22 2018

your question worries me it should be why is my toilet blocking up,you must live in an old house where the drainage is also carrying the surface water,it dont matter what you do ,it will gurgle because the water is pushing up the pipe and the air in front has to go somewhere,


October 23 2018

Please don't use oneshot like someone else said.. I agree with some of the other commitments above but the blockage needs seeing to.. Might be a collapsed drain of something more simple, but impossible to know unless someone has a look.. 're the sink, get an antisiphon trap fitted..


July 05 2020

If you have a cespit make sure it don't need emptying, and anti vac waste as mentioned above.


July 05 2020

If you have a cespit make sure it don't need emptying, and anti vac waste as mentioned above.


July 08 2020

Could be no be trap underneath the basin just elbow or main hole blockage and no air vent on the toilet