Water under suspended floorboards after rain 1930s semi

[beth821]

We have found water (inch or 2) under our suspended floorboards near the joint wall. I don't think it is a leak it comes and goes with the rain. I've seen various google posts that say as long as there is adequate ventilation this is not a problem. We do have several air bricks. it does drain away after a couple of days and I assume it has been like this for years. There is a musty smell but we can't see any particular damage and the joist and floorboards seem dry. The house is on clay soil so I'm wondering if this is just a high water table and not a problem or something we urgently need to address. If we do, who is the best person to advise, a drainage specialist? Does anyone have any experience about this or advice, thank you so much.

We had this. It stopped when we had the old drains relaid (they were old salt-glazed ceramic and they found that the pipes had small cracks in a few places when they dug them up). We replaced with plastic.
Still get a little bit of water in VERY extreme wet weather just along one little bit of wall, pretty sure that is the water table because of where it is, but it rapidly drains away and causes no trouble.

The house did have some damp here and there when we moved in, and a bit of fungus on one or two joists, but we'd got rid of that even before we had the drains done, mostly by making sure all the underfloor vents were unblocked. The fungus died and disappeared of its own accord once the vents were cleared, even before we dealt with the drains (which got rid of the occasional pooling in two or three places).
We're on clay too. The ground under the house is not bone dry, if you kneel on it, you get damp knees, but it is also helping that DH is gradually removing all the rubble and rubbish that the original 1920s builders left under there, which was harbouring moisture. When we moved in, there was plastic sheeting under there for some reason. Surveyor said, get rid of it, so we did. He reckoned it was preventing the underfloor drying out naturally. And he was right.

Good luck with the house.

Thank you so such for replying. We don't have drains near the water it so that's why I am wondering if it was the neighbours. I will see if they will let us do a cctv survey. Good idea to remove all the rubble there is a lot under ours too. If anyone else has had this please let me know.