Waste from upstairs flat ending up in toilet below

[Smudge01]

I'm not a plumber but I was speaking with a customer today who has a strange issue.

When the guy in the 1st floor flat flushes his toilet, his waste ends up in their toilet bowl, they live in the flat below (ground floor) by the way.

I can see from the outside that both toilets are connected into the same soil pipe, it's certainly not a new installation so I can only guess this problem has been going on for many years. Maybe the previous tenants in the ground floor flat didn't mind.

Can anyone advise how best to deal with this problem please?

Thank you in advance.

 

[terryplumb]

Without sight of the soil pipe / layout ,I would suspect a possible blockage .

 

[Iamchamps]

Not even sure how that is possible unless the down stairs toilet has some form of suction device fitted.

 

[Smudge01]

The top arrow shows the toilet above, the bottom arrow shows the toilet below.

 

[terryplumb]

Partially blocked drain ,below ground.

 

[Smudge01]

Is that a job for Dyno Rod or could a local plumber sort that one do you think?

 

[Nige F]

Dyno rod - they've got more chance of getting paid by the landlord - it's their responsibility