Gutters are normally installed to control water run off from a roofing system and to control the water so that it does not result in erosion of soil at the foundation which could result in differential settlement.

There are different methods of controlling water as it is discharged from gutter downspouts.  This can be as upscale as a drainage plumbing system which carries water to the storm sewer or simply splash blocks which prevent water being discharged from the gutter from eroding the soil at the end of the downspout.

In all cases the configuration of the gutter and downspout is important.  The down spout should direct water away from the foundation rather than at or along the foundation and the splash block or drain should carry water far enough away to prevent erosion at the foundation.

Many builders either do not install down spout splash blocks or do not install them correctly.  If they do not exist or if they are installed backwards water will be allowed to run back against the foundation and you will often seen deep holes along the sides of the foundation which can result in poor performance.

Downspout Installed Backward