R317-4-7. Construction and Installation

7.1. System Installation.

A. Approved Plans.

The installer may not deviate from the approved plans or conditions of the construction permit without the approval of the designer and the reviewing regulatory authority.

B. Installation Restrictions.

A regulatory authority may limit the time period or area in which a system can be installed to ensure that soil conditions, weather, groundwater, or other conditions do not adversely affect the reliability of the system.

C. General Requirements.

1. Prior to installation, all minimum setback distances shall be field verified.

2. All absorption areas shall be protected prior to and during site construction.

3. The regulatory authority may require a temporary barrier around the absorption area, including the replacement area for additional protection prior to and during any site construction. If necessary, a more permanent barrier may be required following construction.

4. All absorption excavations and piping shall be level within a tolerance of plus or minus 1 inch. The overall slope from effluent entry to terminus shall be no more than 4 inches per hundred feet.

5. Absorption system excavations shall be made such that the soil in the bottom and sides of the excavation is not compacted. Strict attention shall be given to the protection of the natural absorption properties of the soil.

6. Absorption systems may not be excavated when the soil is wet enough to smear or compact easily.

7. All smeared or compacted surfaces should be raked to a depth of 1 inch, and loose material removed before the absorption system components are placed in the excavation.

8. Open absorption system excavations shall be protected from surface runoff to prevent the entrance of silt and debris.

9. Absorption systems shall be backfilled with earth that is free from stones 10 inches or more in diameter.

10. Distribution pipes may not be crushed or misaligned during backfilling. When backfilling, the earth shall be mounded slightly above the surface of the ground to allow for settlement and prevent depressions for surface ponding of water.

11. Final grading shall prevent ponding throughout the entire system area and promote surface water runoff.

12. Heavy wheeled equipment may not be driven in or over absorption systems prior to or during construction or backfilling.

D. Building and Effluent Sewer.

1. Pipe, pipe fittings, and similar materials comprising building and effluent sewers shall conform to the applicable standards as outlined in Section R317-4-13 Table 4.

2. Each length of pipe shall be stamped or marked as required by the International Plumbing Code.

3. Where two different sizes or types of pipe are connected, a proper type of fitting or conversion adapter shall be used.

4. All sewers:

a. shall have watertight, root-proof joints; and

b. may not receive any ground water or surface runoff.

5. Pipes shall be installed on a foundation of undisturbed earth, or stabilized earth that is not subject to settling.

E. Tanks.

Tank installation shall conform to the following requirements.

1. All tanks shall be installed on a level, stable base that will not settle.

2. The hole to receive the tank shall be large enough to permit the proper placement of the tank and backfill.

3. Where ground water, rock or other undesirable protruding obstructions are encountered, the bottom of the hole shall be excavated an additional 6 inches, and backfilled with sand, crushed stone, or gravel to the proper grade.

4. Backfill around and over the septic tank shall be placed in such a manner as to prevent undue strain or damage to the tank or connected pipes.

F. Absorption Systems.

1. Cover shall be evenly graded over the entire absorption area.

2. Distribution and Drop Boxes.

a. The inlet and outlet piping shall be sealed watertight to the sidewalls of the box.

b. The box shall be provided with a means of access. Access shall be brought to final grade.

c. The lid of the riser shall be adequate to prevent entrance of water, dirt or other foreign material, but made removable for observation and maintenance of the system.

d. The top of the box shall be at least 6 inches below final grade.

e. The box shall be installed on a level, stable base to ensure against tilting or settling, and to minimize movement from frost action.

f. Unused knock-out holes in boxes shall be sealed watertight.

3. The solid and distribution pipes shall be bedded true to line and grade, uniformly and continuously supported by firm, stable material.

4. No cracked, weakened, modified or otherwise damaged chamber or bundled synthetic aggregate units shall be used in any installation.

G. Pressure Distribution.

1. Installation practices shall follow the approved design.

G. Alternative Systems.

1. At-Grade and Mound Systems.

a. The site shall be cleared of surface vegetation, without removing soil, and scarified to an approximate depth of 6 inches. Any furrows resulting from the scarification shall be perpendicular to any slope on the site.

i. Rotary tilling is prohibited for scarification.

b. The system may not be installed in wet or moist soil conditions.

c. No equipment shall be driven over the scarified area.

d. The site shall be graded such that surface water drains away from the system and adjoining area.

2. Packed Bed Media and Sand Lined Trench Systems.

Installation practices shall follow the approved design.