What slope percentage is commonly required for ensuring positive drainage around houses?

A slope percentage of 2% is commonly required to ensure positive drainage around houses because it provides a sufficient gradient for water to flow away from the foundation. This slope ensures that rainwater and meltwater will not accumulate near the structure, which could lead to potential water damage or foundation issues.

In landscaping and drainage design, a 2% slope translates to a decline of 2 units vertically for every 100 units horizontally, which is generally considered an effective balance between enough slope to encourage drainage and maintaining a manageable incline for landscaping and construction purposes. A 2% slope is often the minimum standard recommended in construction guidelines to prevent pooling and ensure effective drainage.

Higher percentages may lead to faster water runoff, but can also complicate landscaping efforts, while lower percentages might not provide adequate drainage, leading to the increased risk of water-related problems.