Washington Administrative Code

R315.2 Where required. Carbon monoxide alarms shall be provided in accordance with Sections R315.2.1 and R315.2.2.R315.2.1 New construction. For new construction, an approved carbon monoxide alarm shall be installed outside of each separate sleeping area in the immediate vicinity…

[Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 10-03-098, § 51-51-0317, filed 1/20/10, effective 7/1/10. Statutory Authority: RCW 19.27.190, 19.27.020, and chapters 19.27 and 34.05 RCW. WSR 08-01-102, § 51-51-0317, filed 12/18/07, effective 4/1/08. Statutory Authority: RC…

[Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 16-03-025, § 51-51-0322, filed 1/11/16, effective 7/1/16; WSR 10-03-098, § 51-51-0322, filed 1/20/10, effective 7/1/10.]

R324.3 Photovoltaic systems. Installation, modification, or alteration of solar photovoltaic power systems shall comply with this section and the International Fire Code. Section R104.11 alternative materials and methods of this code shall be considered when approving the install…

R325.1 General. Mezzanines shall comply with Sections R325 through R325.5. Habitable attics shall comply with Section R326.[Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 20-21-041, § 51-51-0325, filed 10/13/20, effective 11/13/20; WSR 20-03-023, § 51-51-0325, filed 1/6/20…

R326.1 General.Habitable attics shall comply with Sections R326.1 through R326.4.EXCEPTION:Lofts in dwelling units and sleeping units shall be permitted to comply with Section R333, subject to the limitations in Section R333.1.[Statutory Authority: RCW 19.27.031 and 19.27.074. WS…

R327.1 General. The design and construction of swimming pools, spas, and other aquatic recreation facilities shall comply with the 2021 International Swimming Pool and Spa Code, if the facility is one of the following:1. For the sole use of residents and invited guests at a singl…

R328.2 Equipment listings. ESS shall be listed and labeled for residential use in accordance with UL 9540.EXCEPTIONS:1. Where approved, repurposed unlisted battery systems from electric vehicles are allowed to be installed outdoors or in detached sheds located not less than 5 fee…

[Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 23-02-058, 23-12-104, and 23-20-024, § 51-51-0329, filed 1/3/23, 6/7/23, and 9/25/23, effective 3/15/24; WSR 20-03-023, § 51-51-0329, filed 1/6/20, effective 7/1/20; WSR 16-03-025, § 51-51-0329, filed 1/11/16, effective 7/1/1…

R330.1 General. This section shall apply to all newly constructed adult family homes and all existing single-family homes being converted to adult family homes. This section shall not apply to those adult family homes licensed by the state of Washington department of social and h…

R331.1 Family home child care. For family home child care with more than six children, each floor level used for family child care purposes shall be served by two remote means of egress. Exterior exit doors shall be operable from the inside without the use of keys or any special …

R332.1 Protection against radon. The radon control provisions of Appendix F of this code shall apply to buildings constructed in high radon potential counties (zone 1) designated in Table AF101(1). The radon control provisions of Appendix F of this code shall also apply to all bu…

R333.1 General. Where provided in dwelling units or sleeping units, lofts shall comply with this code as modified by Sections R333.1 through R333.5. Lofts constructed in compliance with this section shall be considered a portion of the story below. Such lofts shall not contribute…

R334.1 General. Stationary fuel cell power systems in new and existing buildings and structures shall comply with Section 1206 of the International Fire Code.[Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 23-02-058, 23-12-104, and 23-20-024, § 51-51-0334, filed 1/3/23, 6/…

R403.1.1 Minimum size. The minimum width, W, and thickness, T, for concrete footings shall be in accordance with Tables R403.1(1) through R403.1(3) and Figure R403.1(1) or R403.1.3, as applicable, but not less than 12 inches (305 mm) in width and 6 inches (152 mm) in depth. The f…

[Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 23-02-058, 23-12-104, and 23-20-024, § 51-51-0404, filed 1/3/23, 6/7/23, and 9/25/23, effective 3/15/24; WSR 20-21-041, § 51-51-0404, filed 10/13/20, effective 11/13/20; WSR 16-03-025, § 51-51-0404, filed 1/11/16, effective 7…

R408.1 Ventilation. The under-floor space between the bottom of the floor joists and the earth under any building (except space occupied by a basement) shall have ventilation openings through foundation walls or exterior walls. A ground cover of six mil (0.006 inch thick) black p…

[Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 16-03-025, § 51-51-0501, filed 1/11/16, effective 7/1/16. Statutory Authority: RCW 19.27.031 and chapters 19.27 and 34.05 RCW. WSR 13-04-068, § 51-51-0501, filed 2/1/13, effective 7/1/13.]

[Statutory Authority: RCW 19.27.031 and chapters 19.27 and 34.05 RCW. WSR 13-04-068, § 51-51-0502, filed 2/1/13, effective 7/1/13. Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 10-03-098, § 51-51-0502, filed 1/20/10, effective 7/1/10.]

TABLE R507.3.1MINIMUM FOOTING SIZE FOR DECKSLIVE OR GROUND SNOW LOAD(psf)TRIBUTARY AREA(sq.ft.)LOAD-BEARING VALUE OF SOILSacd (psf)1500e2000e≥ 3000eSide of a square footing(inches)Diameter of a round footing(inches)Thicknessf(inches)Side of a square footing(inches)Diameter of a r…

R602.1.1.1 Used sawn lumber. Used sawn lumber identified with a grade mark, in good condition and devoid of areas of decay shall be assumed to meet the requirements of Section 602.1.1 or shall comply with the following:1. Dimensional lumber not identified with a grade mark that h…

[Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 23-02-058, 23-12-104, and 23-20-024, § 51-51-0608, filed 1/3/23, 6/7/23, and 9/25/23, effective 3/15/24; WSR 20-03-023, § 51-51-0608, filed 1/6/20, effective 7/1/20.]

R609.3 Testing and labeling. Exterior windows and sliding doors shall be tested by an approved independent laboratory, and bear a label identifying manufacturer, performance characteristics and approved inspection agency to indicate compliance with AAMA/WDMA/CSA 101/I.S.2/A440. E…

[Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 16-03-025, § 51-51-0612, filed 1/11/16, effective 7/1/16. Statutory Authority: RCW 19.27.031 and chapters 19.27 and 34.05 RCW. WSR 13-04-068, § 51-51-0612, filed 2/1/13, effective 7/1/13. Statutory Authority: Chapter 19.27 RC…

R702.5 Other finishes. Wood veneer paneling and hardboard paneling shall be placed on wood or cold-formed steel framing spaced not more than 16 inches (406 mm) on center. Wood veneer and hardboard paneling less than 1/4-inch (6 mm) nominal thickness shall not have less than a 3/8…

R703.1.1 Water resistance. The exterior wall envelope shall be designed and constructed in a manner that prevents the accumulation of water within the wall assembly by providing a water-resistant barrier behind the exterior veneer as required by Section R703.2 and a means of drai…

[Statutory Authority: RCW 19.27.031 and chapters 19.27 and 34.05 RCW. WSR 13-04-068, § 51-51-0806, filed 2/1/13, effective 7/1/13. Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 10-03-098, § 51-51-0806, filed 1/20/10, effective 7/1/10. Statutory Authority: RCW 19.27.074, 1…

R903.4.1 Secondary (emergency overflow) drains or scuppers. Where roof drains are required, secondary emergency overflow drains or scuppers shall be provided where the roof perimeter construction extends above the roof in such a manner that water will be entrapped if the primary …

R1001.7.1 Damper. Masonry fireplaces shall be equipped with a ferrous metal damper located at least 8 inches (203 mm) above the top of the fireplace opening. Dampers shall be installed in the fireplace or the chimney venting the fireplace, and shall be operable from the room cont…

R1002.2 Installation.Masonry heaters shall be installed in accordance with this section and shall be a masonry heater type approved by the department of ecology. Masonry heaters shall comply with one of the following:1. Masonry heaters shall comply with the requirements of ASTM E…

R1004.1.1 Emission standards for factory-built fireplaces. No new or used factory-built fireplace shall be installed in Washington state unless it is certified and labeled in accordance with procedures and criteria specified in ASTM E2558 Standard Test Method for determining part…

R1006.4 Passageway. This section is not adopted.R1006.6 Solid fuel-burning appliances and fireplaces. Solid fuel-burning appliances and fireplaces shall be provided with tight-fitting metal or ceramic glass doors, and:1. A source from outside the structure of primary combustion a…

M1201.1 Scope. The provisions of Chapters 12 through 24 shall regulate the design, installation, maintenance, alteration and inspection of mechanical systems that are permanently installed and utilized to provide control of environmental conditions within buildings. These chapter…

M1301.2 Identification. Each length of pipe and tubing and each pipe fitting utilized in a mechanical system shall bear the identification of the manufacturer.EXCEPTION:The manufacturer identification for fittings and pipe nipples shall be on each piece or shall be printed on the…

[Statutory Authority: RCW 19.27.031 and chapters 19.27 and 34.05 RCW. WSR 13-04-068, § 51-51-1302, filed 2/1/13, effective 7/1/13. Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 10-03-098, § 51-51-1302, filed 1/20/10, effective 7/1/10.]

M1307.2 Anchorage of appliances. Appliances designed to be fixed in position shall be fastened or anchored in an approved manner. Thermal storage units shall be anchored or strapped to resist horizontal displacement caused by earthquake motion in accordance with one of the follow…

M1413.1 General. Evaporative cooling equipment and appliances shall comply with UL 1995 or UL/CSA/ANCE 60335-2-40 and shall be installed:1. In accordance with the manufacturer's instructions.2. On level platforms in accordance with M1305.1.3.1.3. So that openings in exterior wall…

[Statutory Authority: RCW 19.27.031 and chapters 19.27 and 34.05 RCW. WSR 13-04-068, § 51-51-1415, filed 2/1/13, effective 7/1/13. Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 10-03-098, § 51-51-1415, filed 1/20/10, effective 7/1/10.]

[Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 10-03-098, § 51-51-1501, filed 1/20/10, effective 7/1/10. Statutory Authority: RCW 19.27.190, 19.27.020, and chapters 19.27 and 34.05 RCW. WSR 08-01-102, § 51-51-1501, filed 12/18/07, effective 4/1/08.]

M1503.2.1 Open-top broiler exhaust. Domestic open-top broiler units shall be provided with a metal exhaust hood, having a minimum thickness of 0.0157 inch (0.3950 mm) (No. 28 gage). Such hoods shall be installed with a clearance of not less than 1/4 inch (6.4 mm) between the hood…

M1504.3 Exhaust openings. Air exhaust openings shall terminate as follows:1. Not less than 3 feet (914 mm) from property lines.2. Not less than 3 feet (914 mm) from gravity air intake openings, operable windows and doors.3. Not less than 10 feet (3048 mm) from mechanical air inta…

M1505.1 General. Where local exhaust or whole-house mechanical ventilation is provided, the ventilation system shall be designed in accordance with this section.EXCEPTION:Alternate balanced whole-house ventilation systems and local exhaust systems designed and commissioned in acc…

[Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 20-12-027, § 51-51-1507, filed 5/27/20, effective 7/1/20; WSR 20-03-023, § 51-51-1507, filed 1/6/20, effective 7/1/20; WSR 16-03-025, § 51-51-1507, filed 1/11/16, effective 7/1/16. Statutory Authority: RCW 19.27.031 and chapt…

[Statutory Authority: RCW 19.27.031 and chapters 19.27 and 34.05 RCW. WSR 13-04-068, § 51-51-1508, filed 2/1/13, effective 7/1/13. Statutory Authority: RCW 19.27.031, 19.27.035, 19.27.074, and chapters 19.27 and 34.05 RCW. WSR 12-07-019, § 51-51-1508, filed 3/12/12, effective 4/1…

M1601.1.1 Above-ground duct systems. Above-ground duct systems shall conform to the following:1. Equipment connected to duct systems shall be designed to limit discharge air temperature to a maximum of 250°F (121°C).2. Factory-made ducts shall be listed and labeled in accordance …

M1701.1 Scope. Solid-fuel-burning appliances shall be provided with combustion air in accordance with the appliance manufacturer's installation instructions. Oil-fired appliances shall be provided with combustion air in accordance with NFPA 31. The methods of providing combustion…

Informational Note: Boilers, water heaters and pressure vessels are regulated by chapter 70.79 RCW and chapter 296-104 WAC in addition to the requirements of this code.Section M2005.1 General. Water heaters shall be installed in accordance with Chapter 5 of the state plumbing cod…

M2101.3 Protection of potable water. The potable water system shall be protected from backflow in accordance with the provisions listed in Section 603 of the state plumbing code.[Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 23-02-058, 23-12-104, and 23-20-024, § 51-51-21…

M2103.3 Piping joints. Copper and copper alloy systems shall be soldered in accordance with ASTM B 828. Fluxes for soldering shall be in accordance with ASTM B 813. Brazing fluxes shall be in accordance with AWS A5.31. Piping joints that are embedded shall be installed in accorda…

M2105.9 CPVC plastic pipe. Joints between CPVC plastic pipe or fittings shall be solvent-cemented in accordance with Section 605 of the state plumbing code. Threaded joints between fittings and CPVC plastic pipe shall be in accordance with Section M2105.9.1.M2105.14 PVC plastic p…