30.23.210 Lot size averaging | Snohomish County Code

30.23.210 Lot size averaging.

(1) A subdivision or short subdivision may meet the minimum lot area requirement of the zone in which it is located by calculating average lot size under this section.

(2) This section shall only apply to:

(a) Subdivisions or short subdivisions within zones having a minimum lot area requirement of 12,500 square feet or less; and

(b) Short subdivisions in rural areas within zones having a minimum lot area requirement greater than 12,500 square feet but not larger than five acres.

(3) Average lot size shall be computed as follows within zones having a minimum lot area requirement of 12,500 square feet or less:

(a) Add together all of the following areas where proposed:

(i) Area in lots;

(ii) Critical areas and their buffers that must be permanently protected under chapter 30.62A SCC;

(iii) Areas designated as open space or recreational uses;

(iv) Areas to be dedicated as right-of-way under chapter 30.66B SCC;

(v) Areas designated as private roads under SCC 30.91R.230; and

(vi) Surface detention/retention facilities meeting the standards of subsection (7) of this section;

(b) Subtract the total lot area from lots that contain existing dwelling units proposed to be retained within the development from the total of subsection (3)(a) of this section;

(c) Divide the lot area calculated in subsection (3)(b) of this section by the total number of lots containing new dwelling units.

(4) Average lot size shall be computed as follows within zones having a minimum lot area requirement greater than 12,500 square feet but not larger than five acres:

(a) Add together all of the following areas where proposed:

(i) Area in lots;

(ii) Critical areas and their buffers that must be permanently protected under chapter 30.62A SCC;

(iii) Areas designated as open space or recreational uses;

(iv) Areas to be dedicated as right-of-way under chapter 30.66B SCC;

(v) Areas designated as private roads under SCC 30.91R.230; and

(vi) Surface detention/retention facilities meeting the standards of subsection (7) of this section;

(b) Subtract the total lot area from lots that contain existing dwelling units proposed to be retained within the development from the total of subsection (4)(a) of this section;

(c) Divide the lot area calculated in subsection (4)(b) of this section by the total number of lots containing new dwelling units.

(5) If the average lot size as computed under either subsection (3) or (4) of this section equals or exceeds the minimum lot area requirement of the zone in which the property is located, then the minimum lot area requirement will be satisfied for the purposes of lot size averaging.

(6) In no case shall the provisions under SCC 30.23.230(3) apply to this section.

(7) Surface detention/retention facilities may count toward calculations for lot size averaging only if the detention/retention facility:

(a) Is designed to not require security fencing under the EDDS standards; and

(b) The facility is either:

(i) Designed so as to appear as a natural wetland system; or

(ii) Provides active or passive recreational benefits in a natural landscaped setting.

(8) For subdivisions and short subdivisions within zones having a minimum lot area requirement of 12,500 square feet or less, the following additional criteria apply:

(a) Each single lot shall be at least 3,000 square feet in area;

(b) Lots in subdivisions and short subdivisions created under the provisions of this section shall have a maximum lot coverage of 55 percent;

(i) A minimum lot width of at least 40 feet; and

(ii) Setbacks of 15 feet from right-of-way and private roads, except that garages must be set back 18 feet from right-of-way (with the exception of alleys) or private roads and corner lots may reduce one right-of-way setback to no less than 10 feet; and

(d) Preliminary subdivisions approved using lot size averaging shall not be recorded by divisions unless such divisions individually or together as cumulative, contiguous parcels satisfy the requirements of this section.

(9) For short subdivisions in rural areas within zones having a minimum lot area requirement greater than 12,500 square feet but not larger than five acres, the following additional criteria apply:

(a) Each single lot shall be at least 12,500 square feet in area or the minimum area necessary to comply with the county health department rules and regulations for on-site sewage disposal and potable water supply, whichever is greater;

(b) Lots in short subdivisions created under the provisions of this section shall have a maximum lot coverage of 35 percent; and

(i) A minimum lot width of at least 75 feet; and

(ii) Setbacks of 50 feet from right-of-way and private roads, except that corner lots may reduce one right-of-way or private road setback to no less than 20 feet. (Added by Amended Ord. 02-064, Dec. 9, 2002, Eff date Feb. 1, 2003; Amended by Amended Ord. 03-075, Sept. 24, 2003, Eff date Oct. 6, 2003; Amended by Amended Ord. 04-081, Sept. 1, 2004, Eff date Sept. 24, 2004; Amended by Amended Ord. 06-061, Aug. 1, 2007, Eff date Oct. 1, 2007; Amended by Amended Ord. 08-101, Jan. 21, 2009, Eff date Apr. 21, 2009; Amended by Amended Ord. 13-042, July 10, 2013, Eff date July 22, 2013; Amended by Amended Ord. 14-073, Oct. 8, 2014, Eff date Oct. 27, 2014; Amended by Ord. 15-065, Oct. 14, 2015, Eff date Oct. 30, 2015; Amended by Amended Ord. 20-005, Mar. 11, 2020, Eff date Mar. 28, 2020; Amended by Amended Ord. 22-016, May 4, 2022, Eff date May 19, 2022; Amended by Amended Ord. 22-062, Oct. 26, 2022, Eff date Jan. 1, 2023).