We have a home that was built last year and the ground has many large cracks formed in it around the house. Should I worry about runoff when the rain starts? We have steep hill and retention wall in yard should I be watering by the house? Any suggestions would be appreciated. I do know that the soil has a lot of clay in it.

I think that just as a general rule, if the ground is dry enough to crack that you should be watering. Soil shifts around the foundation can cause structure compromises.