(a)

1. (1) Primary and secondary absorption areas in a subdivision shall be sized according to natural soil conditions for standard onsite wastewater systems using loading rates found in Table 1.
2. (2) Capping fill systems may be used to overcome separation to bedrock.

3. (3) On lots less than three (3) acres in size proposed for subdivision development, all undisturbed soils shall have a minimum depth of:

   1. (A) Thirteen inches (13”) or greater to a brief seasonal water table;
   2. (B) Eighteen inches (18”) or greater to an adjusted moderate seasonal water table; or
   3. (C) Twenty-four inches (24”) or greater to an adjusted long seasonal water table.
4. (4) Interceptor drains may be used for the purpose of determining minimum lot size when soils exhibiting a brief seasonal water table between the surface and eighteen inches (18”) of depth that an interceptor drain can effectively reduce the depth of the seasonal water table.
5. (5) Lots less than three (3) acres that require interceptor drains in subdivision approval shall include a complete permit submittal to establish siting of the primary and secondary areas, including the interceptor drain.

6. (6)

   1. (A) Drip dispersal design may be used in determining minimum lot size for subdivisions when the following criteria are met:

(i) Minimum depth to bedrock in 14 CAR § 21-602(b)(3);

1. (ii) Primary and secondary absorption areas are flagged on contour; and

   1. (iii) Legal description of primary and secondary absorption areas included in the legal description of those lots.
   2. (B) Lots using drip dispersal design for minimum lot size shall be five-tenths (0.5) of an acre or larger.

(b) Submission shall be made to the local health unit utilizing one (1) of the following approved methods.

1. (1) Subdivision review and soil mapping.

   1. (A) When utilizing soil mapping for subdivision review, the soil map shall be submitted by a professional soil classifier.
   2. (B) When soil mapping a subdivision for the purpose of designing standard onsite wastewater systems, a high intensity map is required.
   3. (C) A high intensity map details the location and extent of the soils and landscape features sufficiently for site evaluation for subsurface wastewater renovation.
   4. (D) The final report consists of a soils map and a soils report.

2. (2) Field procedures for mapping subdivisions.

   1. (A) Soil maps for subdivisions are to be made from a maximum grid of one hundred feet (100’).
   2. (B) Grid points shall be accurately located and identified using flags or stakes.
   3. (C) A soil pit shall be located at each grid point and identified with the corresponding flag or stake.
   4. (D) The maximum distance allowed from a property line to an outside perimeter grid line is fifty feet (50’).
   5. (E) The corners of both the proposed primary and secondary absorption areas shall be sized and flagged on each lot.
   6. (F) A soil description shall be made from each soil pit in accordance with the standards established by the National Cooperative Soil Survey.

3. (3) Soil map.

   1. (A) The soil map should be compiled at a scale of one inch (1”) = one hundred feet (100’) (1:1,200).

   2. (B)

      1. (i)

(b) (b) A map unit is a collection of similar soils defined and named the same in terms of their properties.

1. (c) (c) Each map unit differs in some respect from all others and is uniquely identified on a soil map.

   1. (ii)

(b) (b) Areas of similar soils consisting of six hundred twenty-five square feet (625 sq. ft.) or more shall be delineated.

1. (iii) Areas of contrasting soils consisting of less than six hundred twenty-five square feet (625 sq. ft.):

(b) (b) Shall be identified in the map unit description.

1. (iv)

(b) (b) Example. The unit with the highest loading rate for subsurface wastewater renovation will be named Map Unit 1.

1. (C)

   1. (i) Soil properties critical for sizing of onsite system absorption areas within each map unit shall be given in tabular or narrative form on the soil map or in the soil report.

      1. (ii) These properties include:

(b) (b) Depth to bedrock;

1. (c) (c) Hydraulic conductivity within the depth zone extending six inches (6”) above and twelve inches (12”) below the planned depth of the base of the absorption trench;

   1. (d) (d) Minimum depth to the brief, moderate, and long seasonal water table, if present; and

(e) (e) Minimum loading rate based on these properties.

1. (D)

   1. (i) When a soil pit is not located within the absorption areas, the primary and secondary absorption areas will be sized according to the limiting loading rate within the applicable map unit.

      1. (ii) Within a map unit, the absorption areas can be moved outside the designated primary and secondary areas without additional soils information by utilizing the most limiting loading rate or further soil evaluation in the specific area being proposed shall be conducted.
   2. (E) The map unit legend must identify all symbols used on the soil map.
   3. (F) A signed statement shall be on the soil map certifying the map was made in accordance with the current National Cooperative Soil Survey Standards by a registered professional soil classifier licensed in Arkansas.
   4. (G) The following statement shall be on all soil maps: Any modification such as cutting, filling, or compaction of the soil may change the nature of the soils, and may alter the suitability of the soils for the intended use and will therefore void the soil map.

2. (4) Soil report.

   1. (A) The soil report is a separate document that shall be submitted as an attachment to the soil map.

   2. (B) The report shall consist of the following:

      1. (i)

(b) (b) Terms used in the description shall be those used by the National Cooperative Soil Survey;

1. (ii)

(b) (b) The characteristics shall include but are not limited to color, texture, depth, and type of redoximorphic features, and depth to bedrock.

1. (c) (c) Ranges should be narrow enough that interpretations will not be different for soils with the same typical pedon;

   1. (iii)

(b) (b) The minimum interpretations required include seasonal water table duration, hydraulic conductivity classes, depth to bedrock, and the range of soil loading rate; and

1. (iv) A signed statement shall be on the soil report certifying the report was made in accordance with the current National Cooperative Soil Survey Standards by a registered professional soil classifier.

   1. (c) Sizing is based on seasonal water tables loading rates without soil mapping.

      1. (d)
2. (1) Designated representatives utilizing soil morphology method shall be soil certified.

3. (2) The following information or items shall be included:

   1. (A) A minimum of one (1) soil pit in both the primary absorption and secondary absorption area is required;

   2. (B) Soil pit information shall include:

      1. (i) Depth to bedrock;
      2. (ii) Minimum hydraulic conductivity within the zone extending six inches (6”) above and twelve inches (12”) below the designed depth of the absorption trench;
      3. (iii) Depth and type of restrictive soil layers; and
      4. (iv) Depth to brief, moderate, and long seasonal water tables;
   3. (C) Loading rates based on the soil properties used to size primary and secondary sites shall be given; and
   4. (D) The corners of both the proposed primary and secondary absorption areas shall be sized and flagged on each lot.

(f)

1. (1) Property owners associations that construct and maintain or have constructed and maintained wastewater treatment facilities in accordance with standards and rules established by the department or the Division of Environmental Quality and that desire to exercise general supervision and authority over the treatment of wastewater within and for the subdivided area over which their authority extends, may request the department or in the case of onsite wastewater systems, or the Engineering Section of the Department of Health, in the case of community wastewater treatment systems, to delegate such parts of its authority as the property owners association wishes to exercise.

2. (2) The department may, at its discretion, delegate any of its authority in the administration of this part as it shall deem proper and in accordance with the following:

   1. (A) In the event that such property owners association constructs and maintains all onsite wastewater systems within the subdivided area over which their authority extends, the department, after determining by the procedure set forth in 14 CAR § 21-401 et seq., that the use of the onsite wastewater systems within the subdivision is acceptable, may, at its discretion, delegate the property owners association general supervision and authority over the location, design, construction, installation, and operation of onsite wastewater systems subject, however, to:

      1. (i) Compliance with this part;
      2. (ii) The use of the permit forms established under this part; and
      3. (iii) The final approval of each permit by the authorized agent of the department; and

   2. (B) In the event that such property owners association constructs and maintains all community wastewater treatment systems within the subdivided area over which their authority extends, the Engineering Section of the Department of Health may, at its discretion, delegate general supervision and authority over the location, design, construction, installation, and operation of such community wastewater treatment systems subject to:

      1. (i) Compliance with applicable rules of the department and of the division; and
      2. (ii) Final approval of designs and issuance of permits as required by said applicable rules.
   3. (C) Such compliance shall be to the same degree and extent as would apply if the property owners association were a municipality.