Just noticed this brown stain above my living room window. I don’t have a ladder at the moment so can’t reach it to touch it but the wallpaper near it is starting to lift so I think it might be damp. But it’s on the ground floor and there doesn’t appear to be anything else around it or in the room above it. My bathroom is on the floor above too but to the right. Could it be water travelling from the bathroom down or getting in from outside? It hasn’t rained locally since Saturday.
This depends on where the Op is. Its not uncommon to have pipes in exterior walls in the south and south west US. If this is a bottom floor and there is a room above it could be from an interior fixture like tub/sink/toilet, if its an attic is probably a roof leak. Its also possible that its a wall or window leak but thats less common than a roof leak.
I’m in the UK. There is a radiator with pipes above the window and a boiler in that same room.