Addition rules in Renton's Residential-10 zone

An addition in Renton's Residential-10 zone needs at least 20 ft from the front lot line, 4–15 ft from the rear lot line, depending on the lot type, and at least 4 ft from the side lot line. All buildings together can cover up to 60% of the lot.

Rules last updated 2026-11-05 · This page quotes the Renton Municipal Code. It is a reading aid, not the official code. The City's published code governs. Read the code

Your lot

Addition
HouseDetached ADUAttached ADUAdditionDetached garageShedDeck
Narrow it to your lot
Lot type

Lot type

Corner lots sit on two streets. Through lots run from one street to another.

AnyInterior lotCorner lotThrough lot
Alley

Alley

Is there an alley along the back of the lot?

AnyNo alleyAlley behind the lot
An addition on a typical lot, with its setbacks: Interior lotSTREETFRONT LOT LINEREAR LOT LINESIDE LOT LINESIDE LOT LINEFRONT20′SIDE4′SIDE4′REAR15′Interior lotAn addition on a typical lot, with its setbacks: Corner lotSTREETSIDE STREETFRONT LOT LINEREAR LOT LINESIDE LOT LINESECONDARY FRONT LOT LINEFRONT20′SIDE4′SECONDARY FRONT15′REAR4′Corner lotAn addition on a typical lot, with its setbacks: Through lotSTREETSTREETFRONT LOT LINESECONDARY FRONT LOT LINESIDE LOT LINESIDE LOT LINEFRONT20′SIDE4′SIDE4′SECONDARY FRONT15′Through lotAn addition on a typical lot, with its setbacks: Alley behind the lotSTREETALLEYFRONT LOT LINEREAR LOT LINESIDE LOT LINESIDE LOT LINEFRONT20′SIDE4′SIDE4′REAR15′Alley behind the lot
Setback: no building hereWhere an addition can goA typical lot, not to scale. Your lot's shape, size and conditions change these lines.

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Enter an address and Feasy draws these rules on your actual lot.

What the code allows

Setbacks

iWhat is a setback?
The distance a building has to stay back from a lot line. How the code defines each line ›

A setback is a distance a building has to stay back from a lot line. Here is what the code calls it, and how far an addition has to stay back from each line.

Front

20ftminimum
At least 15 ft when all cars reach the lot from the alley.

At least 20 ft. At least 15 ft when all cars reach the lot from the alley.

How close to the front lot line can an addition be?

What the code says: Renton Municipal Code 4-2-110B

Rear

4–15ftminimum
15 ft · Interior lot4 ft · Corner lot

At least 15 ft. (Interior lot) At least 4 ft. (Corner lot)

How close to the rear lot line can an addition be?

What the code says: Renton Municipal Code 4-2-110B

Side

4ftminimum

At least 4 ft.

How close to the side lot line can an addition be?

What the code says: Renton Municipal Code 4-2-110B

Secondary front

15ftminimum
Corner lot · Through lot

At least 15 ft.

How close to the secondary front lot line can an addition be?

What the code says: Renton Municipal Code 4-2-110B

What the code says · 4-2-110B, 4-2-110I.22

(Amd. Ord. 4963, 5-13-2002; Ord. 4999, 1-13-2003; Ord. 5100, 11-1-2004; Ord. 5132, 4-4-2005; Ord. 5450, 3-2-2009; Ord. 5473, 7-13-2009; Ord. 5518, 12-14-2009; Ord. 5590, 2-28-2011; Ord. 5675, 12-3-2012; Ord. 5726, 10-20-2014; Ord. 5744, 1-12-2015; Ord. 5759, 6-22-2015; Ord. 5790, 4-25-2016; Ord. 5841, 6-12-2017; Ord. 5917, 12-10-2018; Ord. 5960, 12-9-2019; Ord. 6049, 12-13-2021; Ord. 6090, 11-28-2022; Ord. 6160 (Exh. B-2), 6-16-2025) Please see Section 4-2-110I, Conditions Associated With Residential Development Standards Tables, for explanation of table footnotes.

9
1R-10
Minimum Net Density (per Net Acre)1, 2, 155 dwelling units30
Maximum Net Density (per Net Acre, Except per Net 10 Acres in RC)2, 14, 1510 dwelling units29
Maximum Number of Dwellings (per Legal Lot)2Detached dwellings: 1 dwelling unit and up to 2 accessory dwelling units / Attached dwellingsn/a {spans 2 columns}
Minimum Lot Size2, 28, 31Detached dwellings: 4,000 sq. ft. / Attached dwellingsn/a
Minimum Lot Width3140 ft
Minimum Lot Width31 (Corner Lots)50 ft
Minimum Lot Depth3170 ft
Minimum Front Yard4, 5, 3120 ft. except when all vehicle access is taken from an alley, then 15 ft.39
Minimum Rear Yard4, 22, 3115 ft.21, 39
Minimum Side Yard4, 31Detached Units: 4 ft. / Attached Units4 ft. for unattached side(s), 0 ft. for the attached side(s).23
Minimum Secondary Front Yard4, 5, 31 (applies to Corner Lots)15 ft.11 {spans 2 columns}
Maximum Building Coverage (including Primary and Accessory)55%
Maximum Impervious Surface Area70%
Maximum Number of Stories2
Maximum Wall Plate Height8, 9, 10, 12, 18, 1924 ft
Maximum Number of Units per Building24 units
Minimum Freeway Frontage Setback10 ft. landscaped setback from the street property line. {spans 4 columns}
Maximum Wireless Communication Facilities Height (including Amateur Radio Antennas)See RMC 4-4-140, Wireless Communication Facilities. Amateur radio antennas are allowed a maximum height of 6 feet without a Conditional Use Permit. Larger structures will have a maximum height determined by the Conditional Use Permit process, RMC 4-9-030, Conditional Use Permits. {spans 4 columns}
Design StandardsSee RMC 4-2-115, Residential Design and Open Space Standards. {spans 4 columns}
LandscapingSee RMC 4-4-070, Landscaping. {spans 4 columns}
Exterior LightingSee RMC 4-4-075, Lighting, Exterior On-Site. {spans 4 columns}
ScreeningSee RMC 4-4-095, Screening and Storage Height/Location Limitations. {spans 4 columns}
Exception for Pre-Existing Legal LotsSee RMC 4-10-010, Nonconforming Lots. {spans 4 columns}
Renton Municipal Code 4-2-110B · DEVELOPMENT STANDARDS FOR RESIDENTIAL HIGH DENSITY ZONES – PRIMARY STRUCTURES^1

22.        Corner lots required to have a front yard and a secondary front yard are relieved of the requirement to have a rear yard; in place of a rear yard setback, the side yard setback of the zone shall apply.

Renton Municipal Code 4-2-110I.22 · CONDITIONS ASSOCIATED WITH RESIDENTIAL DEVELOPMENT STANDARDS TABLES
How the code defines each line
SETBACK
M. SETBACK: The minimum required distance between the building footprint and the property line and any private access easement or tract. For lots containing private access easements, setbacks are the minimum required distance between the building footprint and the easement. A setback is measured perpendicularly from a lot line or private easement access to the outer wall of the structure. In the case where a structure does not have an outer wall, such as a carport, the measurement shall be to the posts of such structure, unless otherwise determined by the Department of Community and Economic Development.Renton Municipal Code 4-11-190.M
LOT LINES
LOT LINES: The property lines bounding a lot; the designation of lot lines (front, rear, and side) shall be based on the yard designations (see YARD REQUIREMENT).Renton Municipal Code 4-11-120.[LOT LINES]
Lot, Corner
A. Lot, Corner: A lot abutting upon any combination of two (2) or more streets, including private streets (e.g., unit lot drives), access easements, or shared driveways, but excluding alleys, at their intersection, or upon two (2) parts of the same street, such streets or parts of the same street forming an interior angle of less than one hundred thirty-five degrees (135) within the lot lines.Renton Municipal Code 4-11-120.[LOT TYPES].A
Lot, Interior
C. Lot, Interior: A lot that generally abuts or has frontage on only one (1) street (or other means of access that may be permitted).Renton Municipal Code 4-11-120.[LOT TYPES].C
Lot, Through
D. Lot, Through: A lot that has two (2) opposing ends each fronting on a street.Renton Municipal Code 4-11-120.[LOT TYPES].D
YARD REQUIREMENT
YARD REQUIREMENT: An open space on a lot unoccupied by structures, unless specifically authorized otherwise. The Planning Division shall determine the various yard requirements for uniquely shaped lots and flag lots. (See also SETBACK.)Renton Municipal Code 4-11-250.[YARD REQUIREMENT]
Front Yard
A. Front Yard: The yard requirement that separates the structure(s) from public right-of-way, private access easement, or shared driveway. For through lots, corner lots, and lots without street frontage, the front yard will be determined by the Planning Division Director.Renton Municipal Code 4-11-250.[YARD REQUIREMENT].A
Secondary Front Yard
B. Secondary Front Yard: The yard requirement for corner lots and through lots that serves as a second front yard abutting a street right-of-way, private street, or shared driveway.Renton Municipal Code 4-11-250.[YARD REQUIREMENT].B
Rear Yard
C. Rear Yard: The yard requirement opposite the front yard. Where a lot abuts an alley, the rear yard shall always be the yard abutting the alley. For irregularly shaped lots, the rear yard shall be measured from an imaginary line at least fifteen feet (15') in length located entirely within the lot and farthest removed and parallel to the front lot line or its tangent.Renton Municipal Code 4-11-250.[YARD REQUIREMENT].C
Side Yard
D. Side Yard: The yard requirement which is not a front yard, a secondary front yard, or a rear yard.Renton Municipal Code 4-11-250.[YARD REQUIREMENT].D
How setbacks are measured

Height

iWhat is the height limit?
How tall an addition can be, measured the way the code measures height.

Height

24ftwall plate, max
+6 ft for a roof pitched 4:12 or steeperUp to 2 stories

Renton measures from the average ground level along the building's walls. Check with a design professional to confirm your height.

Up to 24 ft. +6 ft for a roof pitched 4:12 or steeper. Up to 2 stories.

How tall can an addition be?

What the code says · 4-2-110B, 4-2-110I.18

(Amd. Ord. 4963, 5-13-2002; Ord. 4999, 1-13-2003; Ord. 5100, 11-1-2004; Ord. 5132, 4-4-2005; Ord. 5450, 3-2-2009; Ord. 5473, 7-13-2009; Ord. 5518, 12-14-2009; Ord. 5590, 2-28-2011; Ord. 5675, 12-3-2012; Ord. 5726, 10-20-2014; Ord. 5744, 1-12-2015; Ord. 5759, 6-22-2015; Ord. 5790, 4-25-2016; Ord. 5841, 6-12-2017; Ord. 5917, 12-10-2018; Ord. 5960, 12-9-2019; Ord. 6049, 12-13-2021; Ord. 6090, 11-28-2022; Ord. 6160 (Exh. B-2), 6-16-2025) Please see Section 4-2-110I, Conditions Associated With Residential Development Standards Tables, for explanation of table footnotes.

9
1R-10
Minimum Net Density (per Net Acre)1, 2, 155 dwelling units30
Maximum Net Density (per Net Acre, Except per Net 10 Acres in RC)2, 14, 1510 dwelling units29
Maximum Number of Dwellings (per Legal Lot)2Detached dwellings: 1 dwelling unit and up to 2 accessory dwelling units / Attached dwellingsn/a {spans 2 columns}
Minimum Lot Size2, 28, 31Detached dwellings: 4,000 sq. ft. / Attached dwellingsn/a
Minimum Lot Width3140 ft
Minimum Lot Width31 (Corner Lots)50 ft
Minimum Lot Depth3170 ft
Minimum Front Yard4, 5, 3120 ft. except when all vehicle access is taken from an alley, then 15 ft.39
Minimum Rear Yard4, 22, 3115 ft.21, 39
Minimum Side Yard4, 31Detached Units: 4 ft. / Attached Units4 ft. for unattached side(s), 0 ft. for the attached side(s).23
Minimum Secondary Front Yard4, 5, 31 (applies to Corner Lots)15 ft.11 {spans 2 columns}
Maximum Building Coverage (including Primary and Accessory)55%
Maximum Impervious Surface Area70%
Maximum Number of Stories2
Maximum Wall Plate Height8, 9, 10, 12, 18, 1924 ft
Maximum Number of Units per Building24 units
Minimum Freeway Frontage Setback10 ft. landscaped setback from the street property line. {spans 4 columns}
Maximum Wireless Communication Facilities Height (including Amateur Radio Antennas)See RMC 4-4-140, Wireless Communication Facilities. Amateur radio antennas are allowed a maximum height of 6 feet without a Conditional Use Permit. Larger structures will have a maximum height determined by the Conditional Use Permit process, RMC 4-9-030, Conditional Use Permits. {spans 4 columns}
Design StandardsSee RMC 4-2-115, Residential Design and Open Space Standards. {spans 4 columns}
LandscapingSee RMC 4-4-070, Landscaping. {spans 4 columns}
Exterior LightingSee RMC 4-4-075, Lighting, Exterior On-Site. {spans 4 columns}
ScreeningSee RMC 4-4-095, Screening and Storage Height/Location Limitations. {spans 4 columns}
Exception for Pre-Existing Legal LotsSee RMC 4-10-010, Nonconforming Lots. {spans 4 columns}
Renton Municipal Code 4-2-110B · DEVELOPMENT STANDARDS FOR RESIDENTIAL HIGH DENSITY ZONES – PRIMARY STRUCTURES^1

18.        Vertical Projections from Wall Plates:

Renton Municipal Code 4-2-110I.18 · CONDITIONS ASSOCIATED WITH RESIDENTIAL DEVELOPMENT STANDARDS TABLES
How Renton measures height
How Renton measures height: Pitched roofPitched roofHow Renton measures height: Flat roofFlat roof

Structure coverage

iWhat counts as coverage?
How much of the lot buildings can cover, counting every structure on the lot together.

Structure coverage

60%of the lot, maximum
BuildingsOpen

Up to 60%.

How much of the lot can buildings cover?

What the code says · 4-2-110B

(Amd. Ord. 4963, 5-13-2002; Ord. 4999, 1-13-2003; Ord. 5100, 11-1-2004; Ord. 5132, 4-4-2005; Ord. 5450, 3-2-2009; Ord. 5473, 7-13-2009; Ord. 5518, 12-14-2009; Ord. 5590, 2-28-2011; Ord. 5675, 12-3-2012; Ord. 5726, 10-20-2014; Ord. 5744, 1-12-2015; Ord. 5759, 6-22-2015; Ord. 5790, 4-25-2016; Ord. 5841, 6-12-2017; Ord. 5917, 12-10-2018; Ord. 5960, 12-9-2019; Ord. 6049, 12-13-2021; Ord. 6090, 11-28-2022; Ord. 6160 (Exh. B-2), 6-16-2025) Please see Section 4-2-110I, Conditions Associated With Residential Development Standards Tables, for explanation of table footnotes.

9
1R-10
Minimum Net Density (per Net Acre)1, 2, 155 dwelling units30
Maximum Net Density (per Net Acre, Except per Net 10 Acres in RC)2, 14, 1510 dwelling units29
Maximum Number of Dwellings (per Legal Lot)2Detached dwellings: 1 dwelling unit and up to 2 accessory dwelling units / Attached dwellingsn/a {spans 2 columns}
Minimum Lot Size2, 28, 31Detached dwellings: 4,000 sq. ft. / Attached dwellingsn/a
Minimum Lot Width3140 ft
Minimum Lot Width31 (Corner Lots)50 ft
Minimum Lot Depth3170 ft
Minimum Front Yard4, 5, 3120 ft. except when all vehicle access is taken from an alley, then 15 ft.39
Minimum Rear Yard4, 22, 3115 ft.21, 39
Minimum Side Yard4, 31Detached Units: 4 ft. / Attached Units4 ft. for unattached side(s), 0 ft. for the attached side(s).23
Minimum Secondary Front Yard4, 5, 31 (applies to Corner Lots)15 ft.11 {spans 2 columns}
Maximum Building Coverage (including Primary and Accessory)55%
Maximum Impervious Surface Area70%
Maximum Number of Stories2
Maximum Wall Plate Height8, 9, 10, 12, 18, 1924 ft
Maximum Number of Units per Building24 units
Minimum Freeway Frontage Setback10 ft. landscaped setback from the street property line. {spans 4 columns}
Maximum Wireless Communication Facilities Height (including Amateur Radio Antennas)See RMC 4-4-140, Wireless Communication Facilities. Amateur radio antennas are allowed a maximum height of 6 feet without a Conditional Use Permit. Larger structures will have a maximum height determined by the Conditional Use Permit process, RMC 4-9-030, Conditional Use Permits. {spans 4 columns}
Design StandardsSee RMC 4-2-115, Residential Design and Open Space Standards. {spans 4 columns}
LandscapingSee RMC 4-4-070, Landscaping. {spans 4 columns}
Exterior LightingSee RMC 4-4-075, Lighting, Exterior On-Site. {spans 4 columns}
ScreeningSee RMC 4-4-095, Screening and Storage Height/Location Limitations. {spans 4 columns}
Exception for Pre-Existing Legal LotsSee RMC 4-10-010, Nonconforming Lots. {spans 4 columns}
Renton Municipal Code 4-2-110B · DEVELOPMENT STANDARDS FOR RESIDENTIAL HIGH DENSITY ZONES – PRIMARY STRUCTURES^1
What Renton counts
What Renton counts
Some cases depend on details a drawing can't show. Check with a design professional for: 4-2-110I.5, 4-11-190.M, 4-2-110I.21

5.        The minimum front yard and secondary front yard setback for lots that abut required turnarounds (cul-de-sacs and hammerheads) may be reduced, excluding garage setbacks, to no less than five feet (5'), subject to the following:

Renton Municipal Code 4-2-110I.5 · CONDITIONS ASSOCIATED WITH RESIDENTIAL DEVELOPMENT STANDARDS TABLES

M. SETBACK: The minimum required distance between the building footprint and the property line and any private access easement or tract. For lots containing private access easements, setbacks are the minimum required distance between the building footprint and the easement. A setback is measured perpendicularly from a lot line or private easement access to the outer wall of the structure. In the case where a structure does not have an outer wall, such as a carport, the measurement shall be to the posts of such structure, unless otherwise determined by the Department of Community and Economic Development.

Renton Municipal Code 4-11-190.M · DEFINITIONS S:

21.        The Community and Economic Development Administrator or designee may modify this provision through the site development plan review process where it is determined that specific portions of the required on-site perimeter landscaping strip may be developed and maintained as a usable public open space with an opening directly to a public entrance.

Renton Municipal Code 4-2-110I.21 · CONDITIONS ASSOCIATED WITH RESIDENTIAL DEVELOPMENT STANDARDS TABLES

Other structures in Renton's Residential-10 zone