stink - but no obvious source!

[marmic]

morning all,

 

We have a stink emanating from somewhere around trap under sink - but no water leak.  1  1/2" plastic waste.  Could the trap be 'faulty' somehow?  It's not dry/blocked etc etc - (no smell from sink).  There's also an elbow after trap.  Both removed, cleaned, reinstalled - but still stinks.  not making any sense -    new fittings maybe?

 

any bright ideas please?  very frustrating!

[Russell griffiths]

Got a picture. 

[MikeSharp01]

Sounds like your system is open to the main sewer, have you got a dry trap somewhere - washing machine for instance or maybe an air admittance valve (AAV) is stuck and your loo flushes are sucking a trap dry.

[FarmerN]

We have a problem with the dishwasher connection but that’s above the trap and smells from the sink and you say “ (no smell from sink)”.

Is it a drain/ sewer smell?

No chance of a dead mouse under/ behind units?