Toilet woes

[Kezzaa]

Hoping you can help with a strange problem - I noticed floor tile grout lines near toilet bowl are getting damp - I dried with a hairdryer but the problem reoccurs within a few hours , even when toilet not flushed. I can’t see/feel any water leaking from waste pipe seal (behind WC) , from cistern, supply line or from fasteners that secure cistern to bowl.
I have attached a couple of photos , the toilet bowl is on the immediate right and the tiled wall is at the top of pics. I wondered if there may be a pipe leak behind tiled walls but I recall that the pipe run at that point has no joins so less likely to be leaking and also you will see in photo 1 the damp patch seems to creep from right to left (toilet outwards) rather than from top to bottom (from wall although that eventually gets damp too).
Any suggestions ? Planning to contact a plumber tomorrow and hoping this is a WC issue since that will be simpler than removing tiles .
Cheers

 

[Riley]

Not much you can say until it’s investigated it could be going up it could be going down

 

[rpm]

Dry tissue paper in hand, start high and work down anywhere you can reach should show the area the leak starts from.

 

[rpm]

Turn water to cistern off if you can, then come back after a few hours and see if water level in cistern has dropped.
Tools required - Pencil to mark water level in cistern.

 

[Kezzaa]

Turn water to cistern off if you can, then come back after a few hours and see if water level in cistern has dropped.
Tools required - Pencil to mark water level in cistern.

I can’t actually turn water to cistern off though so assume fill valve will open to maintain water level ?

 

[rpm]

I can’t actually turn water to cistern off though so assume fill valve will open to maintain water level ?

Yes it will refill, are you sure you can`t see a Silver isolation valve on the pipe putting water into the cistern? If not can you tie up the float using a length of wood and string or wire?