Code of Maine Rules › 10 - DEPARTMENT OF HEALTH AND HUMAN SERVICES › 144 - DEPARTMENT OF HEALTH AND HUMAN SERVICES - GENERAL › Chapter 241 - SUBSURFACE WASTEWATER DISPOSAL RULE › Section 144-241-8 - FIRST-TIME SYSTEMS

Current through 2024-29, July 17, 2024
A.
SETBACKS
				AND SITING FOR FIRST-TIME DISPOSAL SYSTEMS
1. General: Any system, other than
				replacement systems as defined by this rule, designed to serve a specific
				structure or property is a first-time system. The minimum horizontal setbacks
				between first-time disposal system components and site features are set forth
				in Table 8B, except as otherwise authorized in this Section.
2. Reductions in Setback Distances between a
				First-Time Disposal System and a Private Potable Water Supply: If a site
				evaluator determines that it is impractical to install a first-time disposal
				system which is designed to handle 1,000 gpd or less, at least 100 feet from a
				potable water supply, the LPI may authorize the setback reductions set forth in
				Table 8A, provided that reductions are minimized.
TABLE 8A
Reduction in setbacks between a Private Potable Water
				  Supply and a disposal field with a design flow of less than 1,000
				  gpd
Depth of well casing or liner
							 seal below ground level
Reduction in the minimum 100 ft
							 setback distance
40 feet
90 feet
55 feet
80 feet
70 feet
70 feet
90 feet
60 feet
3.
				Additional Setback Reductions Between First-Time Disposal Systems and Site
				Features other than Private Potable Water Supplies which may be Authorized by
				the Department: If a site evaluator determines that it is impractical to
				install a first time disposal system in accordance with Table 8B, the
				Department may authorize additional setback reductions, provided that the site
				conditions and ground water flow are such that the disposal system design will
				offer at least as much protection as would be expected using the setback
				distances prescribed in Table 8B.
4. 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.
5. Disposal fields installed partially in or
				above the original ground: Disposal fields installed partially in or above 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 fill 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% away from the disposal field or conform to the slope of the finish
				grade of the disposal field.
c.
				Fill 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 of
				at least 4 horizontal feet for each vertical foot drop (25% slope) to the
				original ground.
i. The fill extension must
				reach the existing ground before an existing ground slope of 3:1 (33%) or
				within 100 feet horizontal distance of the disposal field; or
ii. A retaining wall of no more than 24
				inches in height that is located no less than 10 feet horizontal distance from
				the outer edge of the shoulder. This provision applies only to soils with AIII,
				B, or C limiting factor conditions, located beneath and down slope of the
				disposal field.