FREQUENTLY ASKED QUESTIONS

The first step in determining if you can operate a business on your property is finding out what the property is zoned. See the Zoning page for information on how to make that determination.

Once you know the zoning of your property, you must consult the Land Use Tables in the Permitted Uses chapter of the King County Code, K.C.C.21A.08.

In general, commercial business are only allowed as the primary use on properties zoned, NB (Neighborhood Business), CB (Community Business), RB (Regional Business), O (Office), and I (Industrial).

If your property is in one of the Resource zones [Agricultural (A), Forestry (F), or Mining (M)], Rural Area zones (RA); or Residential Zones [Urban Reserve (UR), Low density residential (R1-8), or Medium to High-density residential (R12-48)], then a business may only be operated on the property under certain conditions.

Agricultural activities and agricultural support services are usually only permitted in the Rural Area zones, the Urban Reserve Zone, and, of course, in the Agricultural and Forestry zones. Special conditions and limitations do apply and can be found in the Resource land use tables and associated development conditions in King County Code section 21A.08.090.

If your property is located in one of the Rural Area or Residential zones and is being used as your primary residence, then some limited home-based businesses are allowed under the Home Occupation rules contained in King County Code sections 21A.30.080 and 21A.30.090. The following business types are not allowed as a home occupation:

• Automobile, truck and heavy equipment repair
• Auto body work or painting
• Parking and storage of heavy equipment
• Storage of building materials for use on other properties
• Hotels, motels or organizational lodging
• Dry cleaning
• Towing services
• Trucking, storage or self-service, except for parking or storage of one commercial vehicle used in a home occupation
• Veterinary clinic
• Any recreational marijuana related business, and
• Any new winery, brewery, or distillery facility I, II, and III, and remote tasting rooms licensed after December 31, 1999.

Most properties in Unincorporated King County can support an Accessory Dwelling Unit per the provisions of the King County Code.

Only one ADU is allowed per primary detached dwelling unit or townhouse unit, and either the ADU or the primary dwelling unit must be owner-occupied.

Detached ADUs are allowed only on lots that a) contain only one primary dwelling, and b) meet the following lot-size requirements:

*A detached ADU may be built on a RA-5 parcel with a minimum lot size of 2.5 acres if the parcel owner purchases a Transferable Development Right from the rural area. See KCC21A.37 for details.

If the lot is smaller than these minimums, or if it contains more than one primary dwelling, the ADU must be attached to the primary dwelling, or wholly contained in its basement or attic.

ADUs are generally limited to 1000 square feet of heated floor area and 1000 square feet of unheated floor area unless one of the following is true:

• The ADU is wholly contained in the basement or attic of the primary dwelling (or vice-versa), or
• For detached ADUs, the floor area contained in a basement does not count against the total allowed floor area, or
• The lot is zoned RA, and a Transferable Development Right is purchased from the rural area, in which case the smaller of the dwelling units may be up to 1500 square feet.

No additional off-street parking space must be provided for an ADU.

Before beginning the permitting process, an applicant must file an Accessory Dwelling Units: Notice on Title Requirements and Affidavit with the Department of Executive Services, Records and Licensing Services Division.

See KCC21A.08.030, subsection B.7.a, for more detailed information on ADUs.

The first step in determining if you can subdivide your property is finding out what the property is zoned. See the Zoning page for information on how to make that determination.

Once you know the zoning of your property, consult the Density and Dimensions chapter of the King County Code, K.C.C.21A.12.

For Residential and Rural zones (R-1 through R-48, RA-2.5 through RA-20, and UR), see the table in K.C.C.21A.12.030.

For Resource and Commercial/Industrial zones (A-10, A-35, F, M, NB, CB, RB, O, I), see the table in K.C.C.21A.12.040.

To read the tables:

Find your zone designation in the header row at the top of the table. The rows labeled Base Density: Dwelling Unit/Acre and Maximum Density: Dwelling Unit/Acre indicate how many dwelling units, or individual residences, a particular property can accommodate. The Maximum Density is only applicable when utilizing Transfer of Development Rights Credits or Residential Density Incentives and are not explained in these examples. Please contact a Permitting Division Land Use specialist for further questions.

The next step is determining your property’s lot area in acres.
1 acre = 43,560 square feet. To determine your property’s lot area in acres, divide the lot area in square feet by 43,560 square feet.

For example:
A lot area of 7,250 square feet is 0.17 acres. 7,250 s.f./43,560 s.f. = 0.17 acres.

Once you know the lot area in acres, then multiply the lot area in acres times the Base Density: Dwelling Unit/Acre number provide in the table for your property’s zone.

Continuing with the example above: Let’s say the property is in the R-6 zone, which has a Base Density of 6 dwelling units/acre. .17 acres x 6 dwelling units/acre = 1.02 dwelling units, which is rounded down to the nearest whole integer of 1 dwelling unit. Therefore, this property cannot be subdivided.

What if the property were 12,250 square feet in size and similary located in the R-6 zone?
12,250 s.f. / 43,560 s.f. = 0.28 acres
0.28 acres x 6 du/acre = 1.69 dwelling units, which is rounded up to the nearest whole integer of 2 dwelling units. Therefore, this property can be subdivided into 2 parcels.

It is important to note that for properties located in the Rural Area zones, no rounding is allowed when calculating the allowable number of dwelling units. Instead, when calculating the site area for parcels in the RA Zone, if the site area results in a fraction of an acre, the following shall apply: Fractions of .50 or above shall be rounded up to the next whole number and fractions below .50 shall be rounded down. Once the site area is round to the nearest whole acre, no further rounding is allowed.

Example: If the property is located in the Rural Area (RA) zone and the site area in acres is 19.5 acres the site area can be rounded up to 20 acres. No further rounding is allowed.

If this property is zoned RA-5, the calculation would proceed as follows:
19.5 acres is first rounded to 20 acres
20 acres x 0.2 du/ac = 4 dwelling units

If, however, this property measured 19.2 acres in the RA-5 zone, the calculation would proceed as follows:
19.2 acres is rounded to 19 acres
19 acres x 0.2 du/ac = 3.8 dwelling units
Because no further rounding is allowed, this property is only allowed to be subdivided into 3 parcels.

Please review the Residential Density Worksheet for a detailed explanation of calculating the allowable residential density.

To find out what you can build, or how you can use your property, consult the Land Use Tables in the Permitted Uses chapter of the King County Code, K.C.C.21A.08. See the Zoning page for information on how to read the tables.

• For Residential uses (single-family and multi-family homes, group residences, hotel/motel), see 21A.08.030
• For Recreational/Cultural uses (parks, theaters, bowling centers, libraries, museums), see 21A.08.040
• For General Services uses (daycare, veterinary, automotive repair, hospitals and health services, schools), see 21A.08.050
• For Government/Business Services uses (public agencies, construction and trade, professional offices, warehousing and storage), see 21A.08.060
• For Retail uses (stores, restaurants, gas stations, livestock sales), see 21A.08.070
• For Manufacturing uses (winery/brewery, wood products, electronic equipment), see 21A.08.080
• For Resource uses (agriculture, forestry, fish and wildlife management, mineral), see 21A.08.090
• For Regional uses (landfill, wastewater treatment facility, fairground, stadium/arena), see 21A.08.100

In addition to the regulations in the King County Code, your property may be subject to special Development Conditions or Critical Areas restrictions, which can also impact your development options.

Find the setbacks for your zone in the Densities and Dimensions section of the King County Code, K.C.C.21A.12.

For Residential and Rural zones (R-1 through R-48, RA-2.5 through RA-20, and UR), see the table in K.C.C.21A.12.030.

For Resource and Commercial/Industrial zones (A-10, A-35, F, M, NB, CB, RB, O, I), see the table in K.C.C.21A.12.040.

To read the tables:

Find your zone designation in the header row at the top of the table. The rows labeled Minimum street setback and Minimum interior setback will have your base setback requirements.

If there’s a number, or numbers, in parentheses following your setback measurement in the table, that means additional development conditions apply. Find the numbered section(s) in the text immediately following the table for more details.

In addition to the zoning and development conditions, a parcel’s setbacks might be affected by other factors, including:

• Presence of a regional utility corridor
• Presence of an alley
• Nonconforming street setbacks on neighboring lots
• Use of the proposed building (special setbacks apply to livestock or manure storage, for example)

See K.C.C.21A.12.110 – K.C.C.21A.12.160 for details.

Certain structures and projections—bay windows, some uncovered decks and porches, fences, freestanding air conditioners—may be permitted to extend into the setback area. See K.C.C.21A.12.170 for details.

Hazard Tree Removal

King County Code (KCC) chapter 16.82 provides an exemption from permit requirements for trees that pose an “imminent hazard” to persons or structures. An imminent hazard means the tree or portions of the tree could fail at any moment and without warning, and that a target is present. If the tree is a hazard but not an imminent hazard, and greater than 7,000 square feet of the parcel has already been cleared, or if the tree is within certain critical areas or critical area buffers, then a clearing permit is required.

You need a grading permit for:

• Grading within a critical area
• Excavations greater than 5 feet deep or 100 cubic yards
• Any fill greater than 3 feet deep or 100 cubic yards
• Creation of more than 2,000 square feet of new impervious surface

If you need a permit, find the forms under clearing and grading.