Rainwater drainage

[henry1]

My house is mid-terrace. There are gutter downpipes every two houses, so 1 downpipe is shared by two houses. My rear garden slopes towards the house and slightly to the left where the downpipe joins the gully.
So it looks like the slope is on purpose or in any case useful at directing rain water to the gully.

But is this the right situation?

I always thought water should be directed away from a property as it could cause all sorts of problems.

The water is not being directed in the gutter via drain pipes, it just flows towards the lowest point which happens (on purpose or not again?) to be the gully.
The gully seen from outside looks like this:
http://www.screwfix.com/p/square-hopper-gully-grid/13687

But has an additional connection on the side where the downpipe goes straight into it. Of course I don't know how it looks like below ground.
All around there is concrete and concrete paving slabs. Nothing is waterproof of course since there are cracks in the concrete and gaps between the paving slabs. So even if water flows to the gully, a lot will just seep through the concrete around it.

There is no sign of rising damp or any other defects due to water flowing there. Perhaps there is a French drain below the concrete slabs alongside the house? This is a bit too much to hope for...

So I just wanted to know if this is how it should be?

 

[Mikefromlondon]

Yes that is correct the slop directing water towards the gully, a gully is connected underneath to the rest of your drainage system, the gully you are showing is only the top part, it connects to a bottom part called a gully trap and then to the drains. In some areas rain water is drained separately to its own drainage system, as it doesn't then need treatment before discharging into rivers or seas, however in most areas with older drainage system, it is combined with sewage waste and then has to go through the treatment plants to be neutralised or treated before being discharged into rivers or seas.

 

[henry1]

But the surface water flows towards the gully, not directly in it. This means the area around the gully gets flooded with water as the water flows towards it. So some water will simply seep through the gaps in the cement and the gaps are pretty wide. Is there anything underneath that collects this water?

I have a lean-to roof to which I would like to add guttering and direct the water to the gully. However, the gully lies just on the other side of my fence, so I cannot direct the pipe into the gully. What I'm left with is to terminate the pipe on my side of the fence, dumping all the water at the lowest point so it will flow into the gully.

Is it advisable to direct so much water to one place? This water would have fallen at the foot of the house anyway or flowed back to the house due to the slope, so it's not like I'm adding more water.

 

[Mikefromlondon]

yes some water is obviously going to seep through the gaps in your paving slabs, if you are highly concerned you could fill these gaps with mortar, however, unless it was drenching with pouring rain and and thunder, you are not going to get as much seepage as you envisaged, of course soil will absorb as much as it could and this moist soil can affect your brickwork below the damp proof course, above it you need not worry, your house foundations are usually quite deep in order of a meter or more below the ground level resting on hard core soil.

Just make sure your gully is not blocked otherwise water would pool around it.