At least 6 in inches.
The minimum slope for ground adjacent to the foundation is typically recommended to be at least 6 inches over 10 feet. This slope helps to direct water away from the foundation and prevent potential issues such as water seepage and damage to the structure.
The 6 inches over 10 feet slope can also be expressed as a slope ratio of 6:10 or 6/10. This means that for every 10 feet of horizontal distance, the ground should slope up by 6 inches vertically.
It's important to note that the specific requirements for the minimum slope can vary based on local building codes and regulations, as well as the specific characteristics of the site. It's always best to consult with a local building professional or engineer to determine the appropriate slope for the ground adjacent to the foundation in your specific location.