Any idea what causing this

[bccacrcn]

Hi, weird patch on wall behind fridge-

No pipes or metal present near their, and shape and size has not changed in few weeks. Does not feel damp. Wall painted 4 yrs ago. Is not exterior wall. Any ideas what causing?

 

[martygturner]

The heat from cooling a fridge has to go somewhere and along with it goes the condensation off the compressor which normally gets caught in a drip tray under the coils, when they get clogged with dust and pet hair they trap the moisture and hey presto you get a water stain patch up the wall. I would suggest pulling out your fridge and giving the compressor and its cooling coils a hoover...

 

[bccacrcn]

Make sense, I think I also had a book leaning against the fridge and that wall corner, to make matters worse, thanks