Low Density Residential Development Standards

An Accessory Dwelling Unit (ADU) is a small, self-contained residential unit with its own kitchen and bathroom built on the same lot as an existing single family home.

ADU’s are allowed in residential zones if they comply with the zoning and building code standards. Please see the handout, ADUs – Accessory Dwelling Units, for more information.

“Home occupation” (TMC 18.06.430) means an occupation or profession which is customarily incident to or carried on in a dwelling place, and not one in which the use of the premises as a dwelling place is largely incidental to the occupation carried on by a resident of the dwelling place; provided, that:

1. There shall be no change in the outside appearance of the surrounding residential development;
2. No home occupation shall be conducted in any accessory building;
3. Traffic generated by such home occupations shall not create a nuisance;
4. No equipment or process shall be used in such home occupation which creates noise, vibration, glare, fumes, odor, or electrical interference detectable to the normal senses off the lot;
5. The business involves no more than one person who is not a resident of the dwelling; and
6. An off-street parking space shall be made available for any non-resident employee.

Home occupations are required to apply for a business license.

The maximum building footprint is the area of all structures on a given parcel and is dictated by the size of the parcel. Please see this handout for information on how to caluculate your maximum building footprint.

The maximum development area is the area of all structures as well as any impervious surfaces; driveways, walkways, decks, etc. These maximums are as follows:

• 75% on lots less than 13,000 sq. ft., up to a maximum coverage of 5,850 sq. ft
• 45% on lots greater than or equal to 13,000 sq. ft.

The maximum building height in the LDR district is 30′. Height is calculate from the average grade plan to the average roof pitch,

Setbacks for the LDR district are as follows:

• Front yard: 20′
• Second front yard (corner lots): 10′
• Side yard: 5′
• Rear yard: 10′

For more information please see this handout; Calculating Building Heights and Setbacks.

Tukwila’s residential properties are regulated by TMC Chapter 18.54: Urban Forestry and Tree Regulations. Please visit our Urban Forestry webpage for more information on tree maintenance, removal, and installation.

The LDR district is held to the following parking requirements set forth in TMC Figure 18-7:

• 2 for each dwelling unit that contains up to 3 bedrooms.
• 1 additional space for every 2 bedrooms in excess of 3 bedrooms in a dwelling unit.
• Additional parking may be required for home occupations and accessory dwelling units as otherwise required by the zoning code.

Residential Parking and Storage Requirements (18.56.065)

1. Motor vehicles on property devoted to single-family residential use shall be parked on an approved durable uniform surface that is designed to retain surface water on-site and without causing impacts. If necessary, surface water may drain to street if no other design is feasible. Motor vehicles, other than those specified in TMC Section 18.56.065.A.2, shall not be parked in setbacks except in front or secondary front-yard setbacks from streets, when in a driveway that provides access to an approved parking location, and is in conformance with TMC Title 18, as that title currently exists or as it may be subsequently amended. Parking in the rear setback for a single-family home is permitted where the parking is connected to a rear alley.
2. Recreational vehicles, boats or trailers shall be parked, kept or stored on an approved durable uniform surface and shall not be parked, kept or stored in required front yard setbacks, except for a driveway. Recreational vehicle parking in the side or rear yard setbacks is allowed, provided no recreational vehicle is parked so as to prevent access by emergency responders to all sides of a structure.
3. No more than 50% of the front yard or 800 square feet, whichever is smaller, may be approved durable uniform surface. An approved durable uniform surface exceeding this requirement prior to August 25, 2004 may be maintained, but shall not be expanded. The Director of Community Development may approve exceptions to this requirement for an access driveway, particularly on pie-shaped or other odd shaped lots where it is infeasible to meet this requirement.
4. Single-family properties on pre-existing, legal lots of record containing less than 6,500 square feet are exempt from the percentages noted in TMC Section 18.56.065.A.3.
5. No more than six motor vehicles shall be parked on a single-family residential property of 13,000 square feet or less outside of a carport or enclosed garage for a period of more than 48 hours. For purposes of this section, “single-family residential property” means any parcel containing a single-family residence or multiple parcels combined containing one single-family residence, typically identified by a single address located in the LDR zone. The parking limitations in this subsection shall apply to all motor vehicles as defined by state law with the exception of motorcycles and mopeds. (18.56.065 Residential Parking and Storage Requirements).

Single-family homes are required to meet the Design Standards set forth TMC 18.50.050, Single-Family Dwelling Design Standards:

All new single-family dwellings, as well as accessory dwelling units and other accessory structures that require a building permit, must:

1. Be set upon a permanent concrete perimeter foundation, with the space from the bottom of the home to the ground enclosed by concrete or an approved concrete product that can be either load bearing or decorative.
2. If a manufactured home, be comprised of at least two fully-enclosed parallel sections, each of not less than 12 feet wide by 36 feet long.
3. Be thermally equivalent to the current edition of the Washington State Energy Code with amendments.
4. Have exterior siding that is residential in appearance including, but not limited to, wood clapboards, shingles or shakes, brick, conventional vinyl siding, fiber-cement siding, wood-composite panels, aluminum siding or similar materials. Materials such as smooth, ribbed or corrugated metal or plastic panels are not acceptable.
5. Have the front door facing the front or second front yard, if the lot is at least 40 feet wide. This requirement does not apply to ADUs or accessory structures.
6. Have a roofing material that is residential in appearance including, but not limited to, wood shakes or shingles, standing seam metal, asphalt composition shingles or tile, with a minimum roof pitch of 5:12.

The design standards required in TMC Section 18.50.050 (4), (5) and (6) may be modified by the Community Development Director as a Type 2 Special Permission decision. Please see the Tukwila Municipal Code for more information.