How to Calculate Drainage
What is Drainage?
A drainage slope calculator determines the required grade for surface drainage and French drain systems. The minimum slope for surface drainage is 1–2% (1–2 inches per 10 feet); French drains require at least 1% slope (1/8 inch per foot). Inadequate slope causes standing water and foundation problems.
Step-by-Step Guide
- 1Input base values
- 2System computes results
Worked Examples
Input
Enter the required values
Result
Result computed by the formula
Common Mistakes to Avoid
- ✕Precision loss
- ✕Ignoring variables
Frequently Asked Questions
What does this calculator do?
Input base values
How do I use this calculator?
System computes results
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