| Vertical Separation (in inches) |
Horizontal Separation2 | |||||||||||
| < 25 feet | 25 < 50 feet | 50 < 100 feet3 | ≥100 feet | |||||||||
| Soil Type | Soil Type | Soil Type | Soil Type | |||||||||
| 1 | 2 | 3-6 | 1 | 2 | 3-6 | 1 | 2 | 3-6 | 1 | 2 | 3-6 | |
| < 12 | A | A | A | A | A | A | A | A | B | B | B | B |
| ≥ 12 < 18 | A | A | A | A | B | B | A | B | B | |||
| ≥ 18 < 24 | A | A | A | A | B | B | A | B | C | Conforming | ||
| ≥ 24 < 36 | A | B | B | B | C | C | B | C | C | Systems | ||
| ≥ 36 | A | B | B | B | C | C | B | C | E | |||
| 1The treatment component performance levels correspond with those established for treatment components under the product performance testing requirements in Table III of WAC 246-272A-0110. | |
| 2The horizontal separation indicated in Table IX is the distance between the soil dispersal component and the surface water, well, or spring. If the soil dispersal component is up-gradient of a surface water, well, or spring to be used as a potable water source, or beach where shellfish are harvested, the next higher treatment level shall apply unless treatment level A is already required. | |
| 3On a site where there is a horizontal setback of 75 - 100 feet between an OSS dispersal component and an individual water well, individual spring, nonmarine surface water or surface water that is not a public water source and a vertical separation of greater than twelve inches, a conforming system that complies with WAC 246-272A-0210(4) shall be installed if feasible. |