1920s Stormwater Drains - Water always present - Is this Normal?

[subzero]

We have a house which was built in 1925 and there are 3 main stormwater drains serving the guttering downpipes from the roof. There always seems to be a set level of water showing in each, assume this is normal as flushing with a hose they seem to drain away fine but you never see them drain away completely 'empty' as it were.

Another thing, we can't seem to find where they drain to - should there be a separate manhole cover other then the only one we can find which shows the kitchen/bathroom drainage?

 

[bernardgreen]

The gully has a U bend or similar to retain water as a seal to stop fumes and sewer gas coming out. Exactly the same principle as in a toilet pan.

 

[Nige F]

They probably drain into the foul sewer - a combined system - I personally would have a small bit of gutter under that shoe so all the water goes into the gulley over the grid. But then I am a bit pedantic

 

[catlad]

yes its normal