Division 3. General Development Standards
Chapter 21.31
LOT DEVELOPMENT STANDARDS
Sections:
21.31.020 Interpreting tables in this chapter.
21.31.030 Residential zoned lot development standards.
21.31.040 Nonresidential zoned lot development standards.
21.31.050 Additional provisions applicable to residential lot development standards.
21.31.010 Purpose.
This chapter establishes development standards applicable to the creation of lots and residential densities. (Ord. 737 § 2 (Att. A), 2022)
21.31.020 Interpreting tables in this chapter.
When interpreting the tables found in this chapter, the zone districts are located on the vertical columns and the corresponding development standards to each zone are located on the horizontal rows of the tables. (Ord. 737 § 2 (Att. A), 2022)
21.31.030 Residential zoned lot development standards.
(1) The pertinent development standards applicable to lots in each of the corresponding residential zones are set forth in Table 21.31.030.
|
Development Standards1 |
Low Density |
Moderate Density |
Medium Density |
High Density |
||||
|---|---|---|---|---|---|---|---|---|
|
R-1 |
R-4 |
R-6 |
R-8 |
R-12 |
R-18 |
R-24 |
R-48 |
|
|
Minimum Lot Area (Square Feet) |
35,000 |
9,000 |
6,000 |
5,000 |
3,600 |
2,400 |
1,700 |
900 |
|
Maximum Dwelling Units per Lot2 |
2 |
2 |
3 |
3 |
3 |
3 |
3 |
3 |
|
Minimum Street Lot Width (feet) |
75 |
60 |
50 |
30 |
30 |
30 |
30 |
30 |
|
Minimum Lot Width (feet) |
75 |
60 |
50 |
30 |
25 |
25 |
25 |
25 |
|
Maximum Lot Depth to Lot Width3 |
4:1 |
4:1 |
4:1 |
4:1 |
None |
None |
None |
None |
|
Notes: 1. This table excludes “unit lot” subdivisions. 2. See subsection (2) of this section for additional dwelling units per lot. 3. See WMC 21.31.050(5) for measuring lot depth to lot width. 4. See definitions for lot area, street lot width and lot width in WMC 21.11A.130. |
||||||||
(2) Lots exceeding the minimum lot area prescribed in Table 21.31.030 may exceed the maximum dwelling units per lot in Table 21.31.030 as follows:
(a) R-1 Zone. One additional dwelling unit per lot is allowed for each full 43,560 square feet of lot area over the minimum lot area in Table 21.31.030 (e.g., a R-1 lot having up to 78,559 square feet is allowed two dwelling units; a lot having 78,560 square feet and over is allowed three dwelling units; a lot having 122,120 square feet and over is allowed four dwelling units; etc.);
(b) R-4 Zone. One additional dwelling unit per lot is allowed for each full 10,890 square feet of lot area over the minimum lot area in Table 21.31.030 (e.g., a R-4 lot having up to 19,889 square feet is allowed two dwelling units; a lot having 19,890 square feet and over is allowed three dwelling units; a lot having 30,780 square feet and over is allowed four dwelling units; etc.);
(c) R-6 Zone. One additional dwelling unit per lot is allowed for each full 7,260 square feet of lot area over the minimum lot area in Table 21.31.030 (e.g., a R-6 lot having up to 13,259 square feet is allowed three dwelling units; a lot having 13,260 square feet and over is allowed four dwelling units; a lot having 20,520 square feet and over is allowed five dwelling units; etc.);
(d) R-8 Zone. One additional dwelling unit per lot is allowed for each full 5,445 square feet of lot area over the minimum lot area in Table 21.31.030 (e.g., a R-8 lot having up to 10,444 square feet is allowed three dwelling units; a lot having 10,445 square feet and over is allowed four dwelling units, a lot having 15,890 square feet and over is allowed five dwelling units; etc.);
(e) R-12 Zone. One additional dwelling unit per lot is allowed for each full 3,630 square feet of lot area over the minimum lot area in Table 21.31.030 (e.g., a R-12 lot having up to 7,229 square feet is allowed three dwelling units; a lot having 7,230 square feet and over is allowed four dwelling units, a lot having 10,860 square feet and over is allowed five dwelling units; etc.);
(f) R-18 Zone. One additional dwelling unit per lot is allowed for each full 2,420 square feet of lot area over the minimum lot area in Table 21.31.030 (e.g., a R-18 lot having up to 4,819 square feet is allowed three dwelling units; a lot having 4,820 square feet and over is allowed four dwelling units, a lot having 7,240 square feet and over is allowed five dwelling units; etc.);
(g) R-24 Zone. One additional dwelling unit per lot is allowed for each full 1,815 square feet of lot area over the minimum lot area in Table 21.31.030 (e.g., a R-24 lot having up to 3,514 square feet is allowed three dwelling units; a lot having 3,515 square feet and over is allowed four dwelling units, a lot having 5,330 square feet and over is allowed five dwelling units; etc.);
(h) R-48 Zone. One additional dwelling unit per lot is allowed for each full 907 square feet of lot area over the minimum lot area in Table 21.31.030 (e.g., a R-48 lot having up to 1,806 square feet is allowed three dwelling units; a lot having 1,807 square feet and over is allowed four dwelling units, a lot having 2,714 square feet and over is allowed five dwelling units; etc.);
(3) Unit lots created by a unit lot subdivision process are not eligible under this section for adding additional dwelling units and are governed by the development standards prescribed for unit lot subdivisions in WMC 21.91.190. (Ord. 792 § 16, 2025)
21.31.040 Nonresidential zoned lot development standards.
Within the NB, TB, CBD, GB, O, T/I, I, P/I and P zones:
(1) Minimum lot area, minimum street lot width, and maximum lot width to lot depth standards do not apply;
(2) The minimum lot width is 25 feet;
(3) Where Table 21.21.050 allows residential use in these zones, the number of dwelling units allowed on a lot shall be based on compliance with the applicable residential floor area ratio prescribed for the zone pursuant to WMC 21.32.050 rather than a units per lot standard. (Ord. 792 § 17, 2025)
21.31.050 Additional provisions applicable to residential lot development standards.
The provisions in this section apply in combination with the residential lot development standards in WMC 21.31.030.
(1) Maximum Dwelling Units. The maximum dwelling units per lot in Table 21.31.030 means the total number of dwelling units that may be erected on a parent lot regardless of lot size (see definition of “parent lot” in WMC 21.11A.170). Additional dwelling units may be erected on a lot for accessory dwelling units and/or if the lot area satisfies requirements in WMC 21.31.030(2).
(2) Critical Areas. Reductions to the dimensional standards on properties containing a critical area can be found in WMC 21.51.080 or 21.77.050(6) as applicable.
(3) Flag Lots. The minimum street lot width shall not apply to flag lots complying with the requirements in WMC 21.92.030(1)(d) or lots located at the terminal end of a street provided emergency vehicle access and turnaround requirements are satisfied.
(4) Lot Size Averaging. Lot size averaging may be applied to the creation or reconfiguration of parent lots in the R-1, R-4, R-6, and R-8 zones provided:
(a) A minimum of three parent lots are included in the lot size averaging;
(b) The minimum lot area prescribed by Table 21.31.030 may be modified as follows:
(i) The application of averaging does not result in the parent lots having an average lot area less than the minimum lot area for the zone;
(ii) Tracts meeting the definition in WMC 21.11A.210 such as open space, roads, native growth protection area, stormwater facilities, and similar special purposes tracts are excluded from lot size averaging; and
(iii) No parent lot area shall be more than 1.15 times the minimum lot area of the zone, and no parent lot area shall be less than 0.85 times the minimum lot area of the zone;
(c) The total number of lots after lot size averaging is applied shall not exceed the total number of lots allowed by the zone without lot size averaging;
(d) Except for the minimum lot area, all other requirements of the zone apply;
(e) Unit lots are ineligible and excluded from lot size averaging; and
(f) Lot size averaging shall not be used in combination with other Woodinville Municipal Code provisions allowing modifications to lot area requirements.
(5) Lot Depth to Width Ratio. The maximum lot depth to width specified in Table 21.31.030 is expressed as a ratio with lot width being one. The greater the lot depth the higher the ratio.
(a) Lot depth is measured as follows:
(i) The measurement is taken along an imaginary straight line drawn between the midpoint of the street property line to the midpoint of the opposite property line parallel to or within 45 degrees of being parallel to the street property line;
(ii) If the lot does not have a street property line, then the property line that intersects the primary access to the lot shall substitute for the street property line;
(iii) If the lot does not have an opposite property line that is parallel or within 45 degrees of being parallel, then the opposite property line measurement is taken to the most distant point of any other property line forming the lot; and
(iv) The access corridor of flag lots are excluded from measuring lot depth.
(b) Lot width is determined pursuant to WMC 21.93.010(1)(c).
(c) To calculate and obtain the ratio divide the lot’s depth by the lot’s width. For example, a residential lot is 150 feet deep and 75 feet wide. Since 150 feet ÷ 75 feet = 2.0, the depth to width ratio is 2:1.
(d) The Director may approve deviations to the maximum lot depth to width ratio to accommodate the protection of critical areas.
(6) Application of Dwelling Units per Lot Standards. The dwelling units per lot standards in WMC 21.31.030 and the allowances for residential uses in Table 21.21.050 are applied in harmony to determine the composition of housing development permissible by the zone on each lot.
(a) The following examples are intended to assist in interpreting this harmonization:
(i) In the R-1 zone, a 35,000-square-foot parent lot can have up to two dwelling units per lot, which may be comprised of two detached one-unit dwellings, or one building containing two dwelling units (duplex). If the lot is 78,560 square feet or over, the lot may have three dwelling units. Additionally, one of the primary dwelling units can be replaced with two accessory dwelling units pursuant to WMC 21.41.020. However, the configuration of the dwellings must still be one-unit or two-unit buildings. A building containing three or more dwellings is prohibited pursuant to Table 21.21.050.
(ii) In the R-4 zone, a 9,000-square-foot parent lot can have up to two dwelling units per lot, which may be comprised of two detached one-unit dwellings, or one building containing two dwelling units (duplex). If the lot is 19,890 square feet or over, the lot may have three dwelling units. Additionally, one of the primary dwelling units can be replaced with two accessory dwelling units pursuant to WMC 21.41.020. However, the configuration of the dwellings must still be one-unit or two-unit buildings. A building containing three or more dwellings is prohibited pursuant to Table 21.21.050.
(iii) In the R-6 through R-18 zones, all parent lots can have up to three dwelling units per lot, which may be comprised of buildings containing one-unit dwellings, two-unit dwellings (duplex), or three-unit dwellings (townhouses, stacked flat housing). If the parent lot contains sufficient land area, additional dwellings may be added in accordance with WMC 21.31.030(2). Additionally, one of the primary dwelling units can be replaced with two accessory dwelling units pursuant to WMC 21.41.020. With the additional dwelling units, the configuration of the dwellings may be expanded to include buildings containing four or more attached dwelling units (multiplex housing development) pursuant to Table 21.21.050. In the R-12 and R-18 zones, the configuration of dwellings may also be in the form of a multiple dwelling unit development pursuant to Table 21.21.050.
(iv) In the R-24 and R-48 zones, all parent lots must have a minimum of three dwelling units per lot. If the parent lot contains sufficient land area, additional dwellings may be added in accordance with WMC 21.31.030(2). However, the configuration of the uses must be in the form of townhouses, stacked flat housing development, and multiple dwelling unit development. Buildings containing only one or two dwelling units are prohibited pursuant to Table 21.21.050.
(b) The allowance for cottage housing development, courtyard housing development, and stacked flat housing development should not be interpreted to:
(i) Limit the placement or arrangement of buildings on a property; or
(ii) Allow more dwelling units per lot than prescribed in WMC 21.31.030 and 21.41.020.
(c) Figure 21.31.050(6) contains illustrations on different dwelling configurations including one-unit, two-unit, three-unit, etc., buildings to assist in interpreting the provisions of this title.
Figure 21.31.050(6) Examples of Residential Building Types..228125.png)
(Ord. 792 § 18, 2025)