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Little Pocket Apps
Plumber Suite
Professional Tools — Free

Drain Slope Calculator

How much fall does a drain run need? Put in the length and the pipe size, and get the drop in inches, so the water carries the solids all the way out.

The Run
ft
▾
in

Slope Result

Required slope
Total drop over the runMinimum fall from start to end.
Drop per 10 ft

More slope is not better. Too steep and the water outruns the solids, leaving them behind to clog the pipe. Stick close to the minimum slope, and check your local code, some areas want 1/4 inch per foot on everything.