Section 24.17.230 Developments, subdivisions, and minimum land area requirements.

24.17.230 Developments, subdivisions, and minimum land area requirements.

(1) A person proposing a subdivision where the use of an OSS is planned shall obtain a recommendation for approval from the health officer.

(2) The health officer shall require the following prior to approving any OSSs in a proposed development:

(a) Site evaluations as required under Section 24.17.130;

(b) Where a subdivision with individual wells is proposed:

(i) Configuration of each lot to allow a one hundred (100) foot radius water supply protection zone to fit within the lot lines; or

(ii) Establishment of a one hundred (100) foot protection zone around each existing and proposed well site;

(c) Where preliminary approval of a subdivision is requested, provision of at least one (1) soil log per proposed lot, unless the health officer determines existing soils information allows fewer soil logs;

(d) Determination of the minimum lot size or minimum net land area required for the development using Method I and/or Method II:

(i) Method I. Table X—Single-Family Residence Minimum Lot Size or Minimum Net Land Area Required per Unit Volume of Sewage, shows the minimum lot size required per single-family residence. For developments other than single-family residences, the minimum land areas shown are required for each unit volume of sewage. Prior to recommending approval, the health officer may require larger lot sizes where the health officer has identified nitrogen as a concern either through planning activities described in Section 24.17.060 or another process.

Table X—Single-Family Residence Minimum Lot Size or Minimum Net Land Area Required per Unit Volume of Sewage
Type of Water Supply	Soil Type (Defined by Section 24.17.130)
Type of Water Supply	1	2	3	4	5	6
Public	0.5 acre	12,500 sq. ft.	15,000 sq. ft.	18,000 sq. ft.	20,000 sq. ft.	22,000 sq. ft.
Individual well, on each lot	1 acre	1 acre	1 acre	1 acre	2 acres	2 acres

(ii) Method II. A minimum land area proposal using Method II is acceptable only when the designer justifies the proposal through a written analysis of the:

(A) Soil type and depth;

(B) Area drainage, and/or lot drainage;

(D) Setbacks from property lines, water supplies, etc.;

(E) Source of domestic water;

(F) Topography, geology, and ground cover;

(G) Climatic conditions;

(H) Availability of public sewers;

(I) Activity or land use, present and anticipated;

(J) Growth patterns;

(K) Reserve areas for additional subsurface treatment and disposal;

(L) Anticipated sewage volume;

(M) Compliance with current planning and zoning requirements;

(N) Possible use of alternative systems or designs including the use of systems designed for removal of nitrogen;

(O) Existing encumbrances, such as those listed in Sections 24.17.130(2)(a)(iv) and 24.17.140(6)(j);

(P) Estimated nitrogen loading from OSS effluent to existing ground and surface water; and

(Q) Any other information required by the health officer.

(iii) Shows development with public water supplies having:

(A) At least twelve thousand five hundred (12,500) square feet lot sizes per single-family residence; and

(B) No more than three and one-half (3.5) units volume of sewage per day per acre for developments other than single-family residences;

(iv) Shows development with individual water supplies having at least one (1) acre per unit volume of sewage; and

(v) Shows land area under surface water is not included in the minimum land area calculation; and

(e) Regardless of which method is used for determining required minimum lot sizes or minimum land area, submittal to the health officer of information consisting of field data, plans, and reports supporting a conclusion the land area provided is sufficient to:

(i) Install conforming OSSs;

(ii) Assure preservation of reserve areas for proposed and existing OSSs;

(iii) Properly treat and dispose of the sewage; and

(iv) Minimize public health effects from the accumulation of contaminants in surface and ground water;

(f) The health officer shall require lot areas of twelve thousand five hundred (12,500) square feet or larger except when a person proposes:

(i) An OSS within the boundaries of a recognized sewer utility having a finalized assessment roll; or

(ii) A planned unit development with:

(A) A signed, notarized, and recorded deed covenant restricting any development of lots or parcels above the approved density with the density meeting the minimum land area requirements of subsection (2)(d) of this section;

(B) A public entity responsible for operation and maintenance of the OSS, or a single individual owning the OSS;

(D) Extinguishment of the deed covenant and higher density development allowed only when the development connects to public sewers;

(g) The health officer may:

(i) Allow inclusion of the area to the centerline of a road or street right-of-way in a Method II determination under subsection (2)(d)(ii) of this section to be included in the minimum land area calculation if:

(A) The dedicated road or street rights-of-way are along the perimeter of the development;

(B) The road or street rights-of-way are dedicated as part of the proposed development; and

(I) Require detailed plot plans and OSS designs prior to final approval of subdivision proposals;

(II) Require larger land areas or lot sizes to achieve public health protection;

(III) Prohibit development on individual lots within the boundaries of an approved subdivision if the proposed OSS design does not protect public health by meeting requirements of these regulations; and

(IV) Permit the installation of an OSS, where the minimum land area requirements or lot sizes cannot be met, only when all of the following criteria are met:

1. The lot is registered as a legal lot of record created prior to the effective date of the ordinance codified in this chapter;

2. The lot is outside an area identified by the local plan developed under Section 24.17.060 where minimum land area has been listed as a design parameter necessary for public health protection; and

3. The proposed system meets all requirements of this chapter other than minimum land area;

(h) The use of a reduced-size SSAS does not provide for a reduction in the minimum land area requirements. Site development incorporating reduced-sized SSAS must meet the minimum land area requirements established by this chapter. (Sec. 24 of Ord. 2007-10-01; amended by Sec. 20 of Ord. 2021-11-05)