10-144 C.M.R. ch. 241, § 12 - QUALITY ASSURANCE AND QUALITY CONTROL

A. INSTALLATION

1. General: On sites with fine soil textures, excavations that expose the bottom and sidewall area of the disposal field must not be carried out when the soil moisture content is above the plastic limit, and except when correcting a nuisance, there is no practical alternative, the LPI agrees, and special construction techniques are used. The absolute plastic limit can be estimated by rolling the soil with the fingers. If the soil forms a wire or rod 1/8th of an inch in diameter and does not crumble when handled, the soil moisture content is too high to proceed with the excavation. Septic systems should not be installed when the seasonal water table is high.

2. Any excavation related to the installation of subsurface wastewater disposal systems must comply with Maine's Dig Safe Law at 23 MRS §3360-A, which places certain notification requirements on any person performing excavations.

B. SITE PREPARATION

1. Site preparation requirements: Prior to the placement of any backfill material, the ground surface must be prepared as follows:

a. Soil erosion and sediment control: In areas adjacent to a water body or wetlands, preventative erosion and sediment control measures must be employed consistent with Section 13(C).

b. Clearing: Vegetation must be cut and removed from the area where backfill material is to be placed.

2. Grubbing: The area under the disposal area must have the organic soil horizon removed, including but not limited to all stumps and roots.

3. Scarify the site: The area under the disposal area must be thoroughly roughened. If plowing is used, it must be done parallel to the topographic contour in such a direction that each plow furrow will be thrown up-slope. The soil should be broken up to a depth of six to eight inches. Alternatively, a rototiller or the teeth of a backhoe or frost tooth may be used.

4. Transitional horizon: On sites where the backfill material is coarser than the original soil, a minimum of four inches of backfill material must be mixed into the original soil to form a transitional horizon beneath the disposal area.

5. Fill large holes: If large holes are left as a result of stump and/or stone and/or any removal of the "A" or "Ap" (plow layer) soil horizon these holes must be filled with suitable backfill material that meets the requirements of Section 12(E).

C. EXCAVATION

1. Excavation requirements: Any excavation required for the installation of a disposal field must comply with all the requirements in this Section.

2. Bottom of disposal field: The bottom of each disposal field must be installed at the elevation specified on the permit. It must be maintained to a level grade no greater than 2 inches within 100 feet. Note: The bottom of a disposal field serves as the final stage of the distribution network.

3. Avoid unnecessary compaction: Excavation must be carried out in a manner that will avoid unnecessary compaction of both sidewalls and bottom area. Heavy equipment, especially rubber-tired vehicles such as front-end loaders, should not be driven over the exposed bottom of the disposal field. Excavation should be carried out when possible, by a back-hoe operating from outside the perimeter of the previously excavated portions of the disposal fields.

4. Reopen smeared or compacted bottom or sidewall surfaces: If any portion of the bottom or sidewalls becomes smeared or compacted, that portion must be scarified to reopen soil pores. Rototilling may be necessary to reach the limit of compacted soil depth.

5. Weather conditions: Work should be scheduled so that excavated areas are not exposed to rainfall or wind-blown silt. Any loose soil or debris that is washed or otherwise deposited within the excavation must be carefully removed prior to backfilling. Additionally, disposal fields should not be installed in frozen ground or when the ambient air temperature is below freezing, especially if construction will take place over several days.

D. CONSTRUCTION

1. Construction: The installer of the system must make certain that the system and all its component parts are installed in conformance with the requirements of this rule, the plan prepared by the site evaluator, and with any special engineering design requirements approved or required by the Department, pursuant to an approved variance.

2. Soil and backfill material: The installer of the system must make certain that the construction and installation are performed without adversely affecting the capacity of the soil or backfill material to adequately absorb or treat the septic tank effluent.

E. BACKFILL PLACEMENT FOR DISPOSAL AREAS INCLUDING FILL EXTENSIONS

1. General: Selection and placement of backfill must comply with the requirements of this Section.

2. Backfill standards: The backfill material must be gravelly coarse sand which meets the requirements of Table 12A or 12(E)(2)(a) below, as approved by the Department or LPI:

TABLE 12A Backfill Textural Gradation

Sieve Size	Percent Passing by Weight
3 inches	100
#4	75-100
#10	50-100
#60	10-50
#100	2-20
#200	2-8
Clay Fraction	0-2

a. Field determination of backfill: Due to the difficulty of obtaining sieve analyses and the variability of backfill material, the following procedures can be used in the field to determine the suitability of backfill material. The backfill is suitable if the soil texture is loose single grains, the individual sand grains can be readily seen (similar to salt or sugar grains) and felt, and the following conditions are observed: If squeezed in the hand when dry, it will fall apart when the pressure is released but has enough fines to stain the lines in the palm of the hand; or, if squeezed when moist, it will form a cast that will crumble when touched and bears very careful handling; and it does not form a ribbon between the thumb and forefinger but has enough fines to stain the lines in the palm of the hand.

b. Coarser material beneath or beside disposal system: Stone meeting the requirements of Section 12(F)(2) may be placed immediately adjacent to the disposal field, provided that the rest of the backfill material meets the requirements of Section 12(E). If used beneath the disposal field, it must be considered part of the disposal field for determining the separation between the limiting factor and the bottom of the disposal system.

c. Fill material placement above disposal system: Immediately above the filter fabric or proprietary devices, fill is required as specified on the plans. It must be a minimum of 8 inches in thickness (including cover material).

d. Cover material: Immediately above the backfill or fill material, at least 4 inches of soil or soil and soil amendment mix, suitable for establishment of a good vegetative cover, must be placed over the entire disturbed soil area, including fill extensions.

3. Disposal fields installed completely in the original ground: If the disposal field is completely installed in original ground, the backfill material must completely cover the disposal fields. The disposal field must be adequately crowned on level disposal fields (3 percent minimum grade) to allow for settling so that surface water will be allowed to drain from the site without ponding.

4. Disposal fields installed partially in the original ground: Disposal fields partially installed in the original ground must meet the following requirements:

a. Extent of backfill material: The fill layer must include any backfill beneath the disposal field, the shoulders, and the backfill material extensions surrounding the disposal field on all sides.

b. Shoulder width and slope: The minimum required shoulder width is 3 feet. The finished grade of the shoulder must be sloped at 3 percent away from the disposal field or conform to the slope of the finish grade of the disposal field.

c. Backfill material extension: At the outside edge of the shoulder, the backfill material must be terminated by sloping the top of the backfill layer downward at a slope specified in Sections 8(A)(5)(c) and 9(B)(5)(c), to the original ground if possible, or a man-made retaining wall, provided the retaining wall is no more than 24 inches in height and the horizontal distance from the outer edge of the fill shoulder to the retaining wall is at least 10 feet and the system is located in AIII, B or C conditions, as described in Table 5(E).

F. DISPOSAL FIELDS

1. Installation requirements: Disposal fields which include in a trench configuration, must be installed in compliance with all the requirements in this Section and Section 7(N).

a. Pitch of distribution pipes or proprietary disposal devices: Maximum tolerance of distribution pipes or proprietary disposal devices must be no more than 2 inches in 100 feet.

b. Spacing between distribution pipes: The space between distribution pipes for low pressure distribution must be from 75 to 80% of the hole spacing. Spacing must be equal and uniform.

c. Holes in low pressure distribution pipes: The holes in low pressure distribution pipes must be equal and uniform. The holes must be aligned, so that holes in adjacent distribution pipes are offset by 50% of the hole spacing.

d. Proprietary devices: Proprietary disposal devices approved by the Department as substitutes for disposal field stone and perforated distribution pipes, must be installed, per the manufacturer's instructions.

2. Disposal field stone: The stone used in disposal fields must meet the following requirements:

a. General: Where used, the stone must cover the distribution pipes and extend the full width and length of the disposal field.

b. Thickness: The disposal field stone depth for beds must extend at least 7 inches beneath the bottom of the distribution pipes and must extend at least 1 inch above the top of the distribution pipes. For disposal trenches, disposal field stone depth must extend at least 12 inches beneath the bottom of the distribution pipes and must extend at least 1 inch above the top of the distribution pipes.

c. The disposal field stone must be clean, uniform in size and free of fines, dust, ashes, or clay. It must conform to one of the nominal stone sizes listed in Table 12B.

i. Stone specifications: A site evaluator may define a more stringent standard for stone size for any particular system.

d. The disposal field stone may be loaded onto the disposal field site, using a back-hoe, front-end loader, or dump truck. This operation must be carried out from the sides of the disposal field, rather than by driving onto the prepared area of the disposal field. In the case of large disposal fields, tracked equipment may be operated within the disposal field. This equipment must not exert a ground pressure in excess of eight pounds per square inch. The disposal field stone must be pushed in front of the vehicle, such that a minimum of one foot of stone is maintained beneath the vehicle track and the original soil surface.

TABLE 12B

Maximum Percent passing by weight

	Nominal Stone Size
Sieve Size	1 ½ inches	¾ inches
2 inches	100	100
1 ½ inches	95 - 100	100
¾ inches	0 - 40	90 - 100
½ inches	0 - 20	0 - 55
3/8 inches	0 - 8	0 - 25
#4	0 - 5	0 - 10
#200	0 - 2	0 - 2

3. Covering the disposal field stone: The disposal field stone must be covered with a layer of filter fabric, as the laying of the distribution pipes progresses.

4. Covering the stone with filter fabric:

a. Overlapping filter fabric sheets: Edges of adjacent sheets of fabric must be overlapped by a minimum of 6 inches; and

b. Fabric requirements: The filter fabric specified in the system design must have: adequate tensile strength to prevent ripping during installation and backfilling, adequate air permeability to allow free passage of gases; and adequate particle retention to prevent downward migration of soil particles into the disposal field. The minimum physical properties for the fabric must be 4.0 ounces/square yard (per ASTM D-5261).

5. Waterproof paper prohibited: The use of waterproof paper to cover a disposal field is prohibited.

G. FINAL GRADING

1. General: Final grading for vegetative stabilized disposal areas must be carried out in compliance with the requirements of this Section.

2. Cover material: At least 4 inches of soil or soil/soil amendment mix, suitable for establishment of a good vegetative cover must be placed over the entire filled area including the fill material extensions.

3. Final grading: Final grading must be completed in such a manner that surface water will not collect over the disposal field.

4. Erosion control: Immediately after completion of final grading, the fill material surface must be stabilized by mulching and seeding, or sodding, to establish a good vegetative cover to prevent erosion.

5. Vegetative covers: Grass, clover, trefoil, vetch, perennial wild flowers, or other herbaceous perennials may be utilized for disposal field surfaces.

6. Other covers: Bark chips, woodchips, and other organic materials may be used as cover material when specified by the designer.

7. Woody shrubs and trees: Woody shrubs or trees are unacceptable on disposal field surfaces. Woody shrubs may be used in conjunction with a hardy perennial ground cover on backfill material extensions only.

H. CURTAIN DRAINS

1. Requirements: Curtain drains, when required, must be up-slope of the disposal field, approximately perpendicular to the flow of ground water, intercepting and diverting groundwater away from the disposal field.

2. Setbacks: The minimum distance between the disposal field and a curtain drain must be as follows:

a. Setback up-slope: A minimum setback distance of 10 feet must be maintained between a curtain drain and the up-slope edge of a disposal field. The curtain drain must be located beyond the toe of the uphill fill extension, if the uphill extension is greater than 10 feet and constructed so that the curtain drain is located to prevent any under drain of the disposal field.

b. Setback cross-slope: A minimum setback distance of 15 feet must be maintained between a curtain drain and the ends of a disposal field and constructed, so that the curtain drain is located to prevent any under drain of the disposal field.

c. Free-flowing outlets: Free-flowing outlets must be provided down-slope of the curtain drain extensions. Outlets must meet the following requirements:

i. Discharge point: Outlets may empty into a drainage swale discharging to a surface water body, a groundwater recharge basin, or a gravel bed; and

ii. Outlet design: Outlets must be designed, installed, located, and maintained in a manner that does not cause soil erosion, surface flooding, or damage to adjacent properties, does not create a public nuisance, and does not violate any applicable federal, State, or local laws or regulations

d. Rodent control: Adequate measures must be taken to protect each outlet from the entry of rodents or other small animals.

e. Fill requirements: Fill material over the curtain drain discharge pipes must be of a texture that is similar to, or coarser than, that found at the site and free of large stones, stumps, broken masonry, or other waste construction material.

I. INSPECTIONS

1. Required: It is the duty of the LPI to enforce the provisions of this rule and to make such inspections as may be required by this Section.

2. Required inspections: Any violations of the approved plans and disposal system permit must be noted. The holder of the disposal system permit must be notified of any such discrepancies.

3. LPI's right of entry: In the discharge of duties, the LPI, with the consent of the property owner, occupant, or owner's agent, shall have the authority to enter at any reasonable hour, any structure or premises in the jurisdiction to enforce the provisions of this rule, pursuant to 30-A MRS §4213. If entry is refused, the LPI may seek a court order for entry.

4. Department official's right of entry: In the discharge of duties, Department officials, with the consent of the property owner, occupant, or owner's agent, shall have the authority to enter at any reasonable hour any structure or premises to enforce the provisions of this rule. If entry is refused, the Department may seek a court order for entry.

5. Inspection required: The LPI must perform two inspections as follows:

a. After site preparation: The LPI must inspect the site, after preparation, to ascertain that the vegetation has been cut and removed in the disposal field area, the area under the disposal field and backfill extensions has been roughened, a transitional horizon has been established, and the erosion and sedimentation control measures are in place.

b. Prior to covering the system: The LPI must inspect the site after installation of the system components, including stone, pipes or proprietary devices, tanks, filter fabric, and fill beneath and beside of the disposal area, but before backfill is placed above the disposal system components. This inspection must include any curtain drains, diversion ditches, berms or other measures outlined on the design to improve the function of the system.

6. Notification required: The LPI must be notified at least 24 hours before the system is ready to be inspected.

7. Preparation for inspection: When a system is ready for inspection, the installer must make such arrangements as will enable the LPI to inspect all parts of the system. The installer must have present the proper apparatus and equipment for conducting the inspection and shall furnish such assistance as may be necessary in making a proper inspection.

8. Covering of work: No part of a system may be backfilled until it has been inspected and approved. If any part is covered before being inspected and approved, it must be uncovered at the discretion of LPI and at the expense and risk of the owner.

9. Defects in materials and workmanship: If inspection discloses defective material, design, siting, or poor construction that does not conform to the requirements of this rule, the nonconforming parts must be removed, replaced, and re-inspected.

10. Installer's statement of compliance: The Department will provide a form for the LPI to be given to the homeowner, or the homeowner's agent, at the time of issuing the permit. This form will allow for the site evaluator, installer or inspector, or in the case of an engineered system or a multi-user system a Professional Engineer, to provide a written statement to the owner, or agent, that the system was installed in compliance with this rule and the conditions of the permit, with approval from the LPI.

11. Inspection checklist. The Department will prepare a form that can be used by the LPI and the disposal system installer (contractor) to aid in the proper installation of the disposal system.

J. CERTIFICATE OF APPROVAL

1. Approval: After the required inspection, or, in the case of multiple inspections, when the final inspection indicates the work complies in all respects with this rule and the permit application, a certificate of approval will be issued by the LPI. This approval may be accomplished either by the LPI signing and dating the permit, or by issuing a separate document.

2. 30-day Temporary Use: Upon request of the holder of a disposal system permit, the LPI may issue a 30-day temporary authorization of use before the entire work covered by the disposal system permit has been completed. This authorization may be given only if such portion or portions of the system may be put into service safely, prior to full completion without endangering health or public welfare.

K. WORKMANSHIP

All work must be performed, installed, and completed in a manner that is acceptable to the Department and the LPI according to this rule and any other special consideration.

L. ENFORCEMENT AND VIOLATIONS

1. Unlawful acts: It is unlawful to install, extend, alter, repair, or maintain systems, except in conformity with this rule.

2. Notice of violation: The LPI must serve a notice of violation and order on the person responsible for the installation of work:

a. In violation of the provisions of this rule;

b. In violation of a detailed statement or a plan approved thereunder; or

c. In violation of a disposal system permit or certificate issued under the provisions of this this rule. Such orders must direct the discontinuance of the illegal action or condition and the abatement of the violation.

3. Prosecution: If the notice of violation and order are not complied with promptly, the LPI must demonstrate to the Department that the LPI referred the case to the legal counsel of the jurisdiction, to institute the appropriate proceedings at law or in equity to:

a. Restrain, correct, or abate such violation; or

b. Require removal or termination of the unlawful use of any system in violation of the provisions of this rule or any order or direction made pursuant thereto.

4. Penalties: Any person who violates a provision of this rule, or who fails to comply with any of the requirements thereof, or who installs work in violation of an approved plan or directive of the LPI, or of a disposal system permit issued under the provisions of this rule, shall be subject to the penalties in 30-A MRS §4452(3).

Notes

10-144 C.M.R. ch. 241, § 12