Why does my basin gurgle when toilet is blocked?

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.

Jack - KT6

Asked: March 01 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

APG Assist Plumbing & Gas

March 08 2018

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

Williams Plumbing & Heating

March 08 2018

Because it’s pulling air in when its flushed

JHGD Heating Limited

March 08 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..


October 23 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,

Robin Pearson Plumbing and Heating

March 22 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

Plumber in Croydon

March 13 2018

Just buy some one shot and pour it in the toilet


March 13 2018

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

North London Plumber

March 09 2018

Possibly blockage in the pipework

A W Plumbing and Heating services

March 09 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

Holly Plumbing Services Ltd

March 08 2018

Possible partial or complete blockage in manhole or svp

Kp Drainage

March 08 2018

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

ASN Plumbing & Heating

March 08 2018

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

D R Plumbing Heating and Property Services

March 08 2018