10-144 C.M.R. ch. 241, § 10 - EXPANDED SYSTEMS

A. EXPANSION OF EXISTING DISPOSAL SYSTEMS

1. Scope: This Section governs the expansion of existing systems pursuant to 30-A MRS §4211(3)(A).

2. General: Alterations made to existing disposal systems, excluding those required for an expansion or change in use, may be approved by the LPI, provided that all requirements of Section 3(F) are met, See 5(E)(3).

3. Expansion: For the purposes of this Section, "expansion" means the enlargement or change in use of a structure using an existing subsurface wastewater disposal system that brings the total structure into a classification that requires larger subsurface wastewater disposal system components under this rule, as follows:

a. The initial expansion of a single-family home by the addition of one or more bedrooms, the introduction of mechanically pressurized water to a structure formerly served by hand pumped or hand carried water, replacement of an alternative toilet with a water closet, or an upgrade of the holding tank to a complete system.

b. The initial expansion of a non-residential or a multi-family structure which results in an increase in design flow of 10% or more.

c. Expansions of a structure, such as a porch, living room or sunroom, which do not increase the design flow are exempt from the requirements of this Section.

4. Installation Required: In the following instances, the expanded system design must be installed prior to the expansion of the structure.

a. Any expansion within the Shoreland Zone of major waterbodies/courses.

b. Systems with no valid permitted HHE-200 Form, where expansion is proposed. Verification by an LPI that a system is legally existing as defined, written verification by a site evaluator that the system is complete and functioning properly at the time of evaluation and the issuance of an After-The-Fact permit by the LPI may be substituted for the permitted HHE-200 Form.

c. Systems proposed to be expanded by two or more bedrooms or 25 percent or more of the total design flow for non-residential structures (major expansions).

5. Installation Not Required: The following is required for minor expansions that do not require installation as described in 10(A)(4):

a. Documentation: No person may expand a structure using a subsurface waste water disposal system until documentation is provided to the municipal officers and a notice of the documentation is recorded in the appropriate registry of deeds that, in the event of a future malfunction of the system, the disposal system can be replaced and enlarged to comply with the rules adopted under 22 MRS §42, and any municipal ordinances governing subsurface waste water disposal systems. No requirement of this rule or of any ordinances, may be waived for an expanded structure.

b. Recording designs: The person seeking to expand a structure not requiring installation shall record with the appropriate Registry of Deeds the form prescribed by the Department and the HHE-200 Form for the proposed expanded system. The person seeking to expand a structure not requiring installation shall send copies of the notice by certified mail, return receipt requested, to all owners of abutting lots and to a public drinking water supplier if the lot with the structure that is being expanded is within its source water protection area.

c. Restrictions: After the notice required by this section is recorded, no abutting landowner may install a well on that landowner's property in a location which would prevent the installation of the replacement septic system. The owner of the lot on which the replacement system will be installed may not erect any structure on the proposed site of the replacement system or conduct any other activity which would prevent the use of the designated site for the replacement system.

B. INSTALLATION OF EXPANDED SYSTEMS

1. 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% minimum grade) to allow for settling so that surface water will be allowed to drain from the site without ponding.

2. 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 any 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 ten (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.

C. DESIGN CRITERIA FOR EXPANDED SYSTEMS

Design criteria for expanded systems: The design criteria required for expanded systems is as follows:

1. Outside the shoreland area:

a. Minor Expansion: For the addition of one of the following in an existing dwelling - One bedroom, maximum wastewater flow increase of 25% for non-residential structures, pressurized water introduced to structure, replacement of an alternative toilet with a water closet, or an upgrade of the holding tank to a complete system, then the expansion must meet replacement system criteria, as described in Section 9;

b. Major Expansion: If there is an addition of more than one of the items listed above occurs in an existing dwelling, or there is an increase of wastewater flow greater than 25% for non-residential structures, then the expanded system must meet first-time system criteria, as described in Section 8.

2. Within the shoreland area:

a. Minor Expansion: For the addition of one of the following in an existing dwelling - One bedroom, maximum wastewater flow increase of 25% for non-residential structures, replacement of an alternative toilet with a water closet, or an upgrading of the holding tank to complete the system, then the expansion must meet replacement system criteria to the LPI limits of approval only;

b. Major Expansion: If the addition of more than one of the items listed above occurs in an existing dwelling, and/or the addition of pressurized water to the structure, or an increase of wastewater flow is greater than 25% for non-residential structures, then the expanded system must meet first-time system criteria as described in Section 8.

c. In-law apartments: For the purpose of determining the appropriate design criteria in Sections 10(C)(1)(a) and (b) above, in-law apartments, as defined in this rule, are considered one-bedroom and a minor expansion. The resulting system design must use the design flow of 120 gpd, as required by Table 5A.

Notes

10-144 C.M.R. ch. 241, § 10