Hallo
Has anyone any ideas on what this leak could be. There is water leaking into my flat into the bathroom and hallway from the flat above, this happens every 4/5 days, by the time anyone arrives to look at it the flow has stopped and the cause cannot be found. It is a significant amount of water and would be coming from upstairs hallway/bathroom area.
Thank you
You need to get upstairs when the leak is actually happening and look , it is likedly a shower or bath is leaking and it only happens when the water is running.
4 to 5 days is weird, 7 days would be more understandable. Does upstairs have a weekly clothes wash ?
How regular is it ? Maybe some tank/heating system is overflowing on a 4.5 day cycle.
I think you need to get someone in to check the whole water system anyway, to look for possible causes even if they aren't happening while they are there.
There was a similar problem on here recently. That seemed to be from a boiler upstairs.
In your case, since it's flats, I guess there might be a bathroom directly above yours. You do need to talk to the people upstairs to see if they maybe run a bath or whatever at the times it happens.
I'm really just repeating what Eddie has said.