18A.15.020 Residential Density.
A. Allowable Dwelling Units – Calculating Density.
1. Density provisions shall be calculated in dwelling units per acre (du/ac).
2. Urban. Within urban zone classifications, the allowable number of dwelling units shall be calculated by multiplying the net developable acreage of the site by the allowed density in dwelling units/acres.
a. Net developable acreage is the result of gross site acreage minus:
(1) Environmentally constrained lands;
(2) Private road or vehicle access easements;
(3) Shared access facilities serving two or more lots; and
(4) Public road right-of-way; provided, however, that any portion of proposed or future public right-of-way identified through the Pierce County Transportation Corridors and Connectors Right of Way Preservation Map, Chapter 19D.50 PCC, and not required for the development of the project at the time of application, shall not be deducted from the gross site acreage.
b. Environmentally constrained land includes the following lands identified in the Critical Area Regulations (Title 18E PCC): erosion hazard areas, landslide hazard areas, wetlands, flood hazard areas, and all land below the ordinary high water mark of all lakes, streams, ponds, and tidal waters. The required buffers or setbacks associated with these areas are not included in the definition of environmentally constrained lands.
c. If an applicant is unable to meet minimum density utilizing the definition of net developable acreage, critical area buffers may also be excluded from the net developable acre calculation.
3. Rural and Resource. Within rural and resource zone classifications, the allowable number of dwelling units shall be calculated by multiplying the gross site acreage by the allowed density in dwelling units/acres. The result of these calculations shall equal the number of dwelling units allowed.
a. Gross site acreage is all land, excluding tidelands and any existing public road right-of-way and private road easement, within the boundaries of a development.
4. If a calculation results in a partial dwelling unit, the partial dwelling unit shall be rounded to the nearest whole number. Less than .5 shall be rounded down. Greater than or equal to .5 shall be rounded up.
Examples:
9.2 acres x 4 du/acre = 36.8 (rounded to 37 allowable dwelling units)
17 acres x 1 du/5 acres = 3.4 (rounded to 3 allowable dwelling units)
15 acres x 1 du/10 acres = 1.5 (rounded to 2 allowable dwelling units)
5. In no case shall the rounding provision set forth in subsection A.4 above prevent a project within an urban zone classification from achieving the minimum density required for the zone. In such cases where the minimum density required for the zone would not otherwise be achieved, rounding up of allowable dwelling units shall be used, regardless if the fractional unit is greater than or less than .5.
Example of Project within an SF zone:
Minimum density required for SF zone: 4 du/acre
Project area: 11.1 acres (net)
Allowable units pursuant to (a): 11.1 x 4 du/ac = 44.4
Rounding of units pursuant to (b): 44.4 units, rounded down to 44 units
Resulting Density After Rounding: 44 units/11.1 acres = 3.96 units/acre*
*Does not meet required minimum density, rounding down shall not apply. Allowable dwelling units shall be rounded up from 44.4 to 45, resulting in a density of 4.05 du/acre.
6. On a lot containing both residential and non-residential uses, density shall be based only on that portion of the lot utilized for the residential use. If the residential use is located within the same structure as the non-residential use, the entire lot may be used to calculate density.
7. The residential densities in Rural Centers shall be the same as permitted in the adjacent rural designations. If the Rural Center is abutting more than one rural designation, the least restrictive density provisions will apply, except, when abutting lands within a Case II Volcanic Hazard Area, the more restrictive density shall apply. If the Rural Center is surrounded by resource lands, the density of the resource lands will apply. The densities for senior and assisted-living centers shall be based upon the requirements of the Health Department.
8. For the Shared Housing Use Type, sleeping units which lack private provisions for cooking, eating, or sanitation shall be equivalent to 0.25 dwelling units for purposes of calculating density.
B. Minimum Density.
1. Urban land divisions and residential developments shall comply with Minimum Density, pursuant to Table 18A.15.020-1, for the zone classification in which the proposal is located, unless relief is allowed pursuant to subsection B.2 below.
2. Relief from minimum density is allowed as follows:
a. If a lot is more than 300 feet from a sewer hook-up, the minimum density requirement shall not apply, provided that only one lot of the proposed short plat or subdivision may exceed 7,260 square feet in size and provided improvements associated with the land division do not preclude future access or other improvements needed to achieve minimum density for any future land division.
b. If an applicant is unable to meet minimum density utilizing the definition of net developable acreage in PCC 18.25.030, critical area buffers may be excluded from the net developable acre calculation.
C. Base Density.
1. Land divisions and residential developments may achieve outright the Base Density standard for the zone classification, pursuant to Tables 18A.15.020-1 and -2, in which the proposal is located subject to compliance with all applicable regulations.
D. Maximum Density. In order to exceed Base Density and achieve Maximum Density listed in Tables 18A.15.020-1 and -2, land divisions and residential developments must meet the applicable criteria in this subsection and subsection E below. Maximum Density shall not be exceeded, unless specifically permitted through subsection E below or Chapter 18A.65 PCC.
|
Urban Zone Classification |
Residential Density (du/ac) |
Lot Dimensions |
|||||
|---|---|---|---|---|---|---|---|
|
Minimum |
Base |
Maximum |
Lot Size (square feet) |
Minimum Lot Width (feet) (2) |
|||
|
Mean |
Minimum |
||||||
|
AC |
Activity Center (All County except where listed below) |
8 |
20 |
25 |
N/A |
N/A |
N/A |
|
Gig Harbor |
N/A |
3.5 |
3.5 |
N/A |
6,000 residential |
50 residential |
|
|
15,000 other |
100 other |
||||||
|
CC |
Commercial Center (All County except where listed below) |
8 |
20 |
25 |
N/A |
N/A |
N/A |
|
Gig Harbor |
N/A |
4 |
12 |
N/A |
N/A |
N/A |
|
|
South Hill |
8 |
15 |
20 |
N/A |
N/A |
N/A |
|
|
South Hill* |
6 |
12 |
16 |
N/A |
N/A |
N/A |
|
|
HSF |
High Density Single-Family |
6 |
10 |
18 |
N/A |
N/A |
N/A |
|
MHR |
Moderate High Density Residential (All County except where listed below) |
4 |
10 |
15 |
N/A |
N/A |
N/A |
|
Mid-County |
12 |
20 |
25 |
N/A |
N/A |
N/A |
|
|
Parkland/Spanaway/Midland |
8 |
20 |
25 |
N/A |
N/A |
N/A |
|
|
South Hill |
8 |
15 |
20 |
N/A |
N/A |
N/A |
|
|
MSF |
Moderate Density Single-Family (All County except where listed below) |
4 |
4 |
6 |
5,000 |
4,000 |
50 |
|
Gig Harbor |
4 |
4 |
6 |
N/A |
(3) |
||
|
Parkland/Spanaway/Midland |
4 |
5 |
6 |
5,000 |
4,000 |
50 |
|
|
MUC |
Major Urban Center (All County) |
8 |
20 |
25 |
N/A |
N/A |
N/A |
|
MUD |
Mixed Use District (All County except where listed below) |
6 |
20 |
25 |
N/A |
N/A |
N/A |
|
Gig Harbor |
6 |
15 |
20 |
N/A |
N/A |
N/A |
|
|
Graham (4) |
4 |
10 |
15 |
N/A |
N/A |
N/A |
|
|
Mid-County |
12 |
20 |
25 |
N/A |
N/A |
N/A |
|
|
Parkland/Spanaway/Midland |
12 |
20 |
25 |
N/A |
N/A |
N/A |
|
|
NC |
Neighborhood Center (All County except where listed below) |
4 |
16 |
25 |
N/A |
N/A |
N/A |
|
Gig Harbor |
7,200 residential |
||||||
|
15,000 non-residential |
|||||||
|
Mid-County |
8 |
12 |
16 |
N/A |
N/A |
N/A |
|
|
Parkland/Spanaway/Midland |
6 |
10 |
16 |
N/A |
N/A |
N/A |
|
|
South Hill |
6 |
10 |
12 (5) |
N/A |
N/A |
N/A |
|
|
NCOR |
Neighborhood Corridor |
6 |
25 |
25 |
N/A |
N/A |
N/A |
|
ROC |
Residential/Office/Civic |
6 |
10 |
12 |
N/A |
N/A |
N/A |
|
RR |
Residential Resource (All County) |
1 |
2 |
3 |
N/A |
N/A |
50 |
|
SF |
Single-Family (All County) |
4 |
4 |
4 |
6,000 |
5,000 |
60 |
|
Gig Harbor |
4 |
4 |
4 |
N/A |
(3) |
70 (1) |
|
|
Graham |
4 |
4 |
4 |
9,000 |
7,000 |
75 |
|
|
TCTR |
Towne Center |
15 |
80 |
80 |
N/A |
N/A |
N/A |
|
South Hill |
15 |
25 |
25 |
N/A |
N/A |
N/A |
|
|
UCOR |
Urban Corridor |
12 |
60 |
60 |
N/A |
N/A |
N/A |
|
South Hill |
12 |
25 |
25 |
N/A |
N/A |
N/A |
|
(1)The minimum lot width may be reduced by multiplying the lot area by 0.007.
(2)Minimum lot width does not apply to access easements.
(3)Minimum lot size: MSF = 7,000 sq. ft. for 4 lots or fewer and 4,000 sq. ft. for 5 or more lots; NC = 7,200 square feet residential and 15,000 sq. ft. other; SF = 7,200 sq. ft. for 4 lots or fewer and 5,000 sq. ft. for 5 or more lots.
(4)First floor in multi-level multi-family must be commercial; if not multi-level, a minimum of 50 percent of the total floor area must be commercial.
(5)Maximum density may be increased to 14 for senior housing.
* Code Revisor's Note: The second South Hill row was erroneously included and is incorrect. Please refer to the first South Hill row.
|
Rural and Resource Zone Classification |
Residential Density (du/ac) |
Lot Dimensions |
|||
|---|---|---|---|---|---|
|
Base |
Maximum |
Minimum Lot Dimension (2) |
Minimum Lot Size (5) |
||
|
ARL |
Agricultural Resource Lands (All County except where listed below) |
0.1 |
0.2 (1) |
N/A |
10 acres |
|
Graham |
0.1 |
0.2 |
250 feet in width |
10 acres |
|
|
Key Peninsula |
0.1 |
0.2 |
N/A |
5 acres |
|
|
EPF-RAN |
Essential Public Facility – Rural Airport North |
0.1 |
0.2 |
N/A |
N/A |
|
FL |
Forest Lands (All County except where listed below) |
0.0125 |
0.0125 |
60 feet |
80 acres |
|
Graham |
600 feet in width |
80 acres |
|||
|
R5 |
Rural 5 |
0.2 |
0.2 |
60 feet |
5 acres |
|
R10 |
Rural 10 (All county except where listed otherwise below) |
0.1 |
0.2 (1) |
60 feet |
10 acres |
|
Graham |
0.1 |
0.2 |
250 feet in width (3) |
10 acres |
|
|
R20 |
Rural 20 (All county except where listed otherwise below) |
0.05 |
0.1 |
60 feet |
20 acres |
|
Graham |
0.05 |
0.1 |
250 feet in width (3) |
20 acres |
|
|
R40 |
Rural 40 |
0.025 |
0.0625 (1) |
60 feet |
40 acres |
|
RF |
Rural Farm |
0.1 |
0.2 (1) |
N/A |
10 acres |
|
Alderton-McMillin |
0.1 |
0.2 |
N/A |
10 acres |
|
|
Graham |
0.1 |
0.1 |
250 feet in width (3) |
10 acres |
|
|
Key Peninsula |
0.1 |
0.2 |
N/A |
10 acres |
|
|
PR |
Park and Recreation |
0.1 |
0.2 |
N/A |
N/A |
|
RNC |
Rural Neighborhood Center (All county except where listed otherwise below) |
(4) |
(4) |
(4) |
N/A |
|
RSep |
Rural Separator |
0.2 |
0.4 |
60 feet |
2.5 acres |
|
RSR |
Rural Sensitive Resource |
0.1 |
0.2 |
N/A |
10 acres |
|
Graham |
0.1 |
0.2 |
250 feet in width (3) |
10 acres |
|
|
TC |
Tourist Commercial |
0.1 |
0.2 |
N/A |
N/A |
|
VC |
Village Center |
N/A |
3 |
Maximum residential lot size is 14,750 square feet. |
|
|
VR |
Village Residential |
0.1 |
0.2 |
60 feet |
10 acres |
(1)Maximum density is not allowed in R10 on Anderson Island or in the Upper Nisqually ARL and RF zones.
(2)Minimum lot dimension does not apply to access easements.
(3)Lot width may be reduced to 100 feet in the R10 and 200 feet in the R20, RSR, and RF when it is determined that application of critical area or low impact development requirements would otherwise prevent the allowable density per acre from being achieved or a reasonable building envelope from being attained.
(4)See PCC 18A.15.020.A.7 for RNC density provisions.
(5)The minimum lot size may be reduced as allowed by PCC 18A.15.020.A, Rural; 18A.15.020.E, Density Incentives and Credits; and 18A.15.030.B.3, Lot Dimension – Rural Zones.
E. Density Incentives and Credits.
1. Urban.
a. Urban Open Space. A density incentive of one additional dwelling unit per acre above the base density shall be granted to attain the maximum density in exchange for every five percent of the total gross acreage of the project site designated as urban open space.
b. Transfer of Density. Maximum density may be achieved through the transfer of density credits pursuant to Chapter 18G.10 PCC.
c. Natural Shoreline Environment Designation. New divisions of land within the Natural Shoreline Environment Designation are prohibited from exceeding base density.
d. Senior Housing. "Senior housing" means a development limited to occupants who are at least 55 years of age. Senior housing developments shall only be considered when sewer services are available, housing types are consistent with those allowed in the underlying zone classification, at least two viable modes of transportation serve the development, and when adequate land use controls are prescribed through conditions of a use permit or plat. In the MSF zone classification, maximum density may be increased to eight dwelling units per acre for senior housing. In the HSF and NC zone classifications, the maximum density may be increased to a total of 14 dwelling units per acre for senior housing.
e. Environmentally Constrained Lands Density Credit. In urban areas, a partial on-site density credit shall be given when a site contains environmentally constrained land. The credit shall vary based upon the total percentage of the site that is encumbered by the environmental constraint. The credit provides for an additional percentage increase in the allowable dwelling units permitted in the applicable Density and Dimension Table. On-site density credits shall be given as shown in the Table below.
|
Percentage of site containing environmentally constrained land |
Density credit given |
|---|---|
|
< 20% |
No credit |
|
20% to 50% |
15% increase in allowable dwelling units |
|
50% to 75% |
20% increase in allowable dwelling units |
|
> 75% |
25% increase in allowable dwelling units |
Example of subdivision proposed on a site that is 10 acres in area, including 2.5 acres of environmentally constrained land, and 0.5 acres needed for street right of way.
Maximum density is 6 dwelling units per acre.
Net developable acreage = 10 acres – 2.5 acres (25% environmentally constrained land) – .5 acres (street ROW)
Net developable acreage = 7 acres
7 acres x 6 dwelling units per acre = 42 dwelling units
On-site density credits = 42 dwelling units x 1.15 = 48.3, rounded to 48 dwelling units allowed*.
*If the density credit results in a partial dwelling unit, it shall be rounded to the nearest whole number. Less than 0.5 shall be rounded down. Greater than or equal to 0.5 shall be rounded up.
f. Moderate Density Single-Family. In an MSF zone classification, sanitary sewers are required to achieve a density greater than base density up to maximum density. When dry sewer lines are installed, a residential development up to the maximum density may be allowed in the MSF zone classification; provided, that lots in excess of the density permitted with on-site septic shall not be built upon until the sewer line is extended and connected to all the lots. Shadow lots are transferable and may be sold with the restriction on development.
g. Planned Development District or Planned Unit Development. Maximum density may be achieved through a Planned Development District or a Planned Unit Development pursuant to Chapter 18A.75 PCC.
h. Shadow Platting. "Shadow platting" means lots created as part of a recorded final plat that have been designated for future development when sanitary sewers become available. When dry sewer lines are installed, a residential development up to the maximum density may be allowed; provided, that lots in excess of the density permitted with on-site septic shall not be built upon until the sewer line is extended and connected to all the lots. Shadow lots are transferable and may be sold with the restriction on development.
2. Rural and Resource. When authorized by Table 18A.15.020-2, greater than base density may be achieved, up to maximum density by means of cluster development as specified below in PCC 18A.15.020.E.2a.-g. Cluster development means a development design technique that concentrates buildings or lots in specific areas on a site to preserve the remaining land. Rural and resource density incentives shall not be allowed for properties located in a Case II Volcanic Hazard Area or Natural Shoreline Environment Designation. Open space and associated restrictions shall be designated as such on a recorded document pursuant to the designation criteria of PCC 18A.50.040.
a. Rural Separator.
(1) Two dwelling units per 5 acres (0.4 du/ac), when 50 percent or more of the property is designated as open space shall be permitted.
(2) The maximum number of dwelling units in one cluster shall not exceed 15 principal dwelling units.
b. Rural 10/Tourist Commercial/Village Residential.
(1) Two dwelling units per 10 acres (0.2 du/ac) when 50 percent or more of the property is designated as open space.
(2) The maximum number of dwelling units in one cluster shall not exceed 15 principal dwelling units.
c. Rural 20.
(1) Two dwelling units per 20 acres (0.1 du/ac), when 50 percent or more of the property is designated as open space.
(2) If an adjacent property is classified Forest Land (FL), the required open space tract or easement shall be contiguous with the property classified Forest Land (FL).
(3) The maximum number of dwelling units in one cluster shall not exceed 15 principal dwelling units.
d. Rural 40.
(1) Two dwelling units per 40 acres when 50 percent of the property is designated as open space.
(2) Two and one-half dwelling units per 40 acres when 75 percent of the property is designated as open space.
(3) The maximum number of dwelling units in one cluster shall not exceed 15 principal dwelling units.
e. Rural Sensitive Resource. Two dwelling units per 10 acres (0.2 du/ac) when 50 percent of the property is designated as open space.
f. Park and Recreation. Two dwelling units per 10 acres (0.2 du/ac) when 50 percent of the property is designated as open space.
g. ARL and RF.
(1) When development is clustered, residential density may be increased to a maximum of 1 dwelling unit per 5 acres on properties of 20 acres or more.
(2) The clustered development may not result in more than 10 lots per cluster and only 1 lot may be larger than 1 acre.
(3) The resulting lot greater than 1 acre may contain a single-family home, associated agricultural structures, and other hard surfaces not exceeding 10 percent of the total lot. The remaining area of the larger lot shall be restricted to open space or agricultural use.