I'm wondering if anyone could offer any advice.
We moved in to a 1930's semi in Manchester 10 years ago and I noticed, a few years ago, some water under the floorboards at the front corner of the house. Never really thought too much about it at the time and just thought it must be due to rain etc, but having found rotten joist ends a few months back I thought I'd better take a closer look at why it's there and what's going on.
The water is actually in hole that had been dug in to the clay when a new water mains pipe was fitted at some point in the past (before we moved in), and they did not bother filling the hole back in with the clay they removed under the floor, and it's just piled up alongside the hole.
There is no water anywhere else under the floor in any parts of the house.
I've been monitoring the hole for a few months and it never moves. As in, it never soaks away, but never gets any higher; staying around around 3-4cm lower than the rest of the surrounding ground level. However, if I empty the hole of water (which is around half a washing up bowl worth), it slowly fills back up over a few days, or quicker if it rains. I can't see any route in from above/side and there are no leaks or pipes close to it, apart form the main water pipe. I have had the water board out to check the water in the hole and no chlorine was present and they couldn't find any evidence it's related to the water pipe, just a coincidence that it comes in where the water is standing.
I'm going to replace the floor joists but naturally before doing so I need to find the source of this water, and whether it's an external fault or just ground water table/level. There is no water above the normal clay surface, only in this hole.
I searched this forum and found
this topic which is similar but of course each situation will be unique.
Any thoughts on what I should do? It's not a massive amount of water but enough to make the joists degrade and rot due to the constant stagnant water source.
Images (ignore the rubble, i'll get that cleared out too) below:
N.B. I've been messing with it today so the water is dirty, but normally its crystal clear, and no smell.
Thank you in advance,
J