Drainage tool
Driveway drainage gradient calculator
Measure the run, add the total fall, and get a quick read on whether the gradient is likely strong enough for runoff.
good
Gradient: 1:67
15 mm per metre
This fall works for many domestic drives and sits in a practical range for runoff.
What to do with the result - Strong or good: usually workable if the sub-base and channel details are also right.
- Borderline: inspect shaded areas and slow-draining edges more carefully.
- Poor: treat it as a redesign warning, not just a material-choice issue.