[Bramblecot]

Looks just like the drainage tank at our old farmhouse (built 1870).  There had been gravel at the bottom with an outflow pipe to take the 'clean' water into the orchard. 
Got a quote to clear it out and relay pipes - £££££. so we did it ourselves .  What a mess, but it worked for the next 10 years without a problem.  Of all the nearby houses on private drainage, ours was the only one that never caused a hassle.

[hexhammeasure]

most likely a silt trap, resulting slurry would be collected for use as a fertiliser check the sides for inlets and outlets. DON'T fill it in yet until you are sure its not part of the drains for outbuildings otherwise you might end up flooding them

[Eastling]

We have drained out the water and found it is a metal box with a layer of mud in the bottom. There is one pipe coming from the stables at front of the pig sty.So think it is some sort of drainage system.


There are no other buildings near it. The local farmer who owns the surrounding fields thinks the same. The area has never flooded in the 4 yrs we have been here.

[shygirl]

there is no overflow coming out of it?
personally id leave it rather than fill it in, if its giving no problems as it sounds handy to have.

[Eastling]

It was covered with thick sheets of metal under mud, we have cleared the pathway and found the metal sheeting hence discovering the hole. Need to do something with it to make it safe, We have got weaners coming at the end of the week and don't want sheet metal where they can get to.

[Marches Farmer]

Could you bolt down a sheet of chequerplate? 

[shygirl]

our septic tank is deep but only has a loose metal lid so we weigh it down with concrete blocks. next door have the same but use paving slabs.