Horizontal drainage piping shall be installed in uniform alignment at uniform slopes. The slope of a horizontal drainage pipe shall be not less than that indicated in Table 704.1.
TABLE 704.1 SLOPE OF HORIZONTAL DRAINAGE PIPE
TABLE 704.1 SLOPE OF HORIZONTAL DRAINAGE PIPE
| SIZE (inches) | MINIMUM SLOPE (inch per foot) |
| 21/2 or less | 1/4 |
| 3 to 6 | 1/8 |
| 8 or larger | 1/16 |
For SI: 1 inch = 25.4 mm, 1 inch per foot = 83.33 mm/m.