Large deep manhole

Pinkleylandii

Hi

I have a large deep manhole in my garden. It is connected to my own private drain for foul waste. The manhole is 7ft deep x 5ft wide approx could be wider, it has metal rod stairs. Any idea why I would have such a large manhole serving only 1 drain? Scottish Water said it does not belong to them, they would only adopt a drain if owned by more than one person. So the question that needs to be asked is why so big, it looks like a cave. Need to know as wanting to build on the side. Went down the route of building regs and scottish water, need to provide a drawing of it. Would welcome any input.

chateauneufdupape

Does the manhole definitely only serve your property? I suspect that due to the depth, if there were a problem in the pipe, man entry would be required to sort the problem out. Hence the large diameter. Also building it originally would have been difficult if the diameter was small. Scottish Water will have standard details for manholes which depend on the pipe diameters and depths.

Manholes are confined spaces which are likely to contain dangerous gasses. Do not be tempted to go down it to have a look. Also, the metal rungs may be rusted away. Many water companies have now banned them.