Section 144-232-4-400.0 - WATER WELL LOCATION400.1Scope: This Chapter governs the horizontal setback distances between new water supply wells and disposal fields, septic tanks, holding tanks and lift stations, and includes standards for the construction of drinking water and open-loop geothermal wells. 400.1.1General: The minimum setback distances from waste water systems set forth in this rule are designed to minimize water well contamination by waste water disposal systems. A well driller must make every reasonable effort to determine the location of all septic system components on the subject property and any adjacent properties of concern. The natural flow of ground water on a particular piece of property, as well as the type of water well and the manner in which it will be constructed, are primary considerations when siting a water well in relationship to a waste water disposal systems. This section establishes minimum setback distances for private wells from waste water disposal fields, septic tanks, holding tanks and lift stations and provides for reductions to those distances for bedrock wells when one or more of the conditions defined in section 400.2 below exists at a drilling site.400.1.2Public water supply wells: The State of Maine Rules Relating to Drinking Water, 10-144 CMR Ch. 231, Section 3, describes the approval process for a new well which will serve a public water supply and states that "no new production well shall be installed prior to preliminary approval being granted in writing by the Department of Health and Human Services." Examples include water districts, mobile home parks, campgrounds, restaurants, apartment buildings and hotels. Any setbacks for public water supply wells from septic systems or other potential sources of contamination shall be determined by the Department of Health and Human Services during the preliminary approval review process. See definition in Chapter 1. Point of Contact is:
Maine Drinking Water Program
#11 State House Station
Augusta, ME 04333-0010
Telephone (207) 287-2070
400.1.3Gravel wells: The minimum setbacks provided for in this Chapter cannot be reduced for gravel wells without a specialty well application as provided for in Section 400.7 having been approved by the Commission prior to drilling.400.2Minimum setback distances between water supply wells, and disposal fields: The minimum horizontal setback distance of a water supply well from a waste water disposal field designed to treat less than 2,000 gpd (gallons per day) is 100 feet, and the minimum horizontal setback distance of a water supply well from a waste water disposal field designed to treat 2,000 gpd or more is 300 feet, except as provided for in Sections 400.3 and 400.7. 400.2.1 Wells intended to serve Public Water Supplies, as defined in Chapter 1 of these rules, must be approved in writing by the Department of Health and Human Services prior to being drilled and shall be constructed with a setback from disposal fields or other potential sources of contamination as required by the Department of Health and Human Services, Drinking Water Program.400.3Reduction in minimum setback distances between bedrock water supply wells and disposal fields: The well driller, after consultation with the property owner or customer, may determine that it is not practical to maintain the minimum setback distances from disposal fields as specified in Section 400.2. In these instances, the minimum setback distance for bedrock water supply wells may be reduced, depending upon the amount of casing or liner seal installed below ground level, as provided in Table 400.1 for the following reasons: a the size of the property is not sufficient to allow for the required setback; orb sufficient setbacks from other potential sources of contamination cannot be met; orc excessive slopes prohibit access; ord the location of permanent structures would result in unreasonable impacts or damage to the structures; ore the location of lakes, ponds, streams or wetlands prohibits meeting the required setback; orf the presence of bedrock at or within three vertical feet the surface would result in unreasonable trenching requirements. In these cases a bedrock well must be installed and the setback reductions set forth in Table 400.1, shall be used. In addition, a Setback Reduction Notification Form as described in Section 400.5 must be completed. All other reasons for reducing the setback from a bedrock well to a disposal field shall require a Specialty Well application approved by the Commission prior to drilling. In no case shall the minimum setback be reduced to less than 60 feet from disposal fields designed for less than 2,000 gpd, or 180 feet in the case of wells with sewage systems designed for 2000 gpd (gallons per day) or more, without written approval of a Specialty Well application as described in Section 400.7 by the Commission.
400.3.1Reduction in minimum setback distances between gravel water supply wells and disposal fields: There is no setback reduction allowed for gravel wells without a Specialty Well application approved by the Commission as described in Section 400.7.Table 400.1
Reduction in disposal field setbacks, for bedrock wells and a Wastewater Disposal Field
| Depth of Well Casing or Liner Seal Below Ground Level | Minimum Setback Distance for Disposal System < 2,000 gpd | Minimum Setback Distance for Disposal System > 2,000 gpd |
| 40 feet | 90 feet | 270 feet |
| 55 feet | 80 feet | 240 feet |
| 70 feet | 70 feet | 210 feet |
| 90 feet | 60 feet | 180 feet |
400.4Minimum setback distances between water supply wells and septic tanks, holding tanks and lift stations: The minimum horizontal setback distance of a water supply well from septic tanks, lift stations, and holding tanks is 60 feet. In no case shall the minimum setback be reduced to less than 60 feet from septic tanks, lift stations or holding tanks without written approval of a Specialty Well application as described in Section 400.7 by the Commission.400.5Setback reduction notification forms: The well driller is required to submit a complete Setback Reduction Notification Form to the Commission, on a form provided by the Commission, for all wells drilled less than 100 feet from a disposal field, or 60 feet from a septic tank, holding tank, or lift station, or 300 feet from a disposal field designed for 2,000 gpd or more. The well driller shall indicate on the form which situation(s) described in Section 400.2. resulted in the reduced setback, or indicate the date Specialty Well approval as described in Section 400.7 was granted by the Commission. The well driller will also include the setbacks achieved, a description of the construction details of the completed well, including the depth of casing seal below ground, the length of any liners and the depth of any liner seals below ground. The form, signed and dated by the property owner and well driller, shall be submitted to the Commission no later than thirty (30) days from the completion of the well. If the Commission reviews the setback reduction notification form and finds the reduction not acceptable, the Commission may order corrective measures to be taken.400.6Water wells located adjacent to property lines: The Maine Subsurface Waste Water Disposal Rules provide for special setback conditions between a well and an abutter's subsequently located waste water disposal field (whether located purposefully or not). Specifically, Sections 702 and 703 of the Waste Water Rules (144A CMR 241, pages 7-2, 7-3 and 7-4, and Tables 700.2, 700.3 and 700.4) establish conditions and requirements for setbacks between wells and proposed disposal fields.400.7Specialty wells: The Commission is authorized to review and approve or deny, in writing, on a case-by-case basis, the location of bedrock wells that cannot meet the setback and/or casing provisions described in Sections 400.2, 400.3 and 400.4, or is a gravel well that cannot meet the setbacks described in Sections 400.2 and 400.4. Application for a Specialty Well shall be made directly to the Commission by a duly licensed well driller on a form provided by the Commission. In such instances, if it is not practical to meet the requirements established by these rules, the Commission may permit the location of water supply wells through a written waiver. In such cases the Commission may prescribe other such conditions as it deems necessary for the protection of public health, including having an independent inspector present during specialty well installation. 400.7.1Registry of Deeds: When the Commission authorizes a waiver, the owner may be required by the Commission to file with the Registry of Deeds, a form clearly stating the particular aspects of the well location with reference to the waste water disposal field. The application form will be provided by the Commission and presented to the owner by the well driller. The well driller shall obtain a copy of the recorded deed covenant form prior to the well being drilled.400.7.2Expiration and transferability: Approved Specialty Well applications shall expire one year from the date of issue unless drilling and construction have been completed or the applicant has requested and received an extension from the Commission in writing prior to the expiration date. Specialty well approvals are not transferable between well drilling companies.400.7.3Setbacks less than 40 feet from a disposal field: Specialty wells required to be less than 40 feet from the nearest septic system disposal field shall be constructed with an annular space of not less than a nominal two (2) inches in radius between the outside of the casing and the inside of the borehole. For example, six (6) inch casing requires a borehole at least ten (10) inches in diameter. This space shall be grouted from bottom to top using methods described in the "Manual of Water Well Construction Practices, Second Addition", published by the National Groundwater Association in 1998, Chapter 4, section 4.5, or another method approved by the Commission. Grout shall be either neat cement grout or high-solids bentonite grout with at least 20% solids by weight or another material approved by the Commission. The casing must have a centralizer installed at the bottom. The Commission may require its independent inspector to be present during the grouting process. A driller that has demonstrated familiarity with the required grouting process may have this requirement waived on a case by case basis. Mixtures used for drilling mud are not suitable for use as sealing grout.10-144 C.M.R. ch. 232, § 4-400.0