Drainage under Leicester’s Victorian streets was laid out for streets rather than for individual houses, and that is still the fact that governs most extension projects here.
A single run frequently serves several properties, passing under gardens and through walls that were built around it, and the manhole in your garden may be the only access point for a system serving four other households. That changes what can be built over, what can be diverted and who has to agree to it. We establish what serves what before a design is settled rather than after.
Where a run belongs to the water company rather than to you, and since 2011 a great many do, building over or close to it needs a build over agreement granted before the concrete goes in. It is a routine application and a serious problem to be caught without, because it surfaces during a sale when you are least able to deal with it.
On the larger villa plots the surface water side is the harder half. A big roof and a large area of hard surfacing produce a great deal of water, and a soakaway only works if the ground will accept it at a useful rate and it is sited a sensible distance from the building and the boundary.
On a system of this age we put a camera down before designing over anything. Our drainage work page covers surveys, repairs and new connections.