Subframe swimming pool

A while ago I noticed a bit of water in the spare tyre well, I have had similar problems twice previously I recall and managed to sort it but this time I have found lots of water in the actual subframe of the car is the cause, by just the amount of water in the subframe sloshing about and getting into the well.

In the middle of the picture is a round hole, I can push a piece of pipe in there and down and suck the water out. 1 Month ago I blew and sucked it all out and threw it around a bit, blew the water out again and so on, also left the car open to dry and I believed all the water was out completely. I went away for a month so the car pretty much sat for this time with the only rain being a massive downpour 1 day after I left and someone giving it a wash and apart from the 1 day rain and wash it has sat in the sun for the full month, but today I put the air gun in again and there is loads of water. Obviously there are what I believe to be three possibility's here, 1 - I didn't get it all out, 2 - the huge downpour on day 1 caused it or 3 - a jet washer/washing it is causing it. The water is very clean and tastes clean.

Has anyone one else come across this please. I have extensivly tired sourcing it by tracking back things like, bungs, seals, third brake light and so on and can find no water tracking. It happens on both sides but I believe the passenger side is just the excess from the drivers side.

Car always sits on a slight slope facing downwards so after getting it all out I parked it the other way to see if this helped.

Edited 7 June, 20233 yr by Morph