Drainage Slope
1/4 inch per foot rule and variants.
Example
You enter
- Rise 1
- Run (same units as rise) 4
- Units rise_run
You get
- Inches per foot 3
- Percent 25 %
- Degrees 14.0362
- Fraction 0.25
Details, formula, and sources
Slope expressed as fraction (1/4 inch per foot), degrees, and percent. Standard horizontal-drainage slopes per IPC 2021 Table 704.1.
IPC 2021 (International Plumbing Code). Section 704, Table 704.1.
Free read-only access at codes.iccsafe.org.
Estimate. AHJ and licensed plumber / gas fitter govern. Verify against the IPC / IFGC edition adopted in your jurisdiction.
Field names used by the API: rise, run, units, in_per_ft, percent, degrees, fraction
- Minimum slope rule 1/4 in per ft for ≤ 2.5 in DWV; 1/8 in per ft for ≥ 3 inIPC 2021 Table 704.1