Renton ADU Zoning Rules & Permit Guide

ADU Regulations in Renton, Washington

Updated September 29, 2026

On the southern shore of Lake Washington in King County, Renton's ADU rules align with Washington's HB 1337. The city's proximity to Boeing and tech employment centers makes ADUs a popular housing option for workforce households.

Below is a summary of the key zoning rules applicable to Accessory Dwelling Units in Renton as of 2026. Regulations are governed by Washington's HB 1337 (2023) which limits local ADU restrictions statewide.

Additional Local Requirements for Renton

• ADU allowed in single-family zones
• Minimum 200 sq ft
• Height limit: 20 ft
• HB 1337 statewide limits apply

Frequently Asked Questions About ADUs in Renton

Can I build an ADU in Renton?

Renton permits ADUs in residential zones. Parking may be required depending on transit proximity.

What is the maximum ADU size allowed in Renton?

ADUs in Renton can be up to 1,000 square feet, subject to the property's zoning and lot coverage limits. Always confirm the exact allowed size with the Renton planning department before designing your project.

What are the setback requirements for an ADU in Renton?

ADUs in Renton generally require setbacks of 5 ft rear, 5 ft side. Washington's HB 1337 (2023) limits how restrictive local ADU rules can be, but the exact setback figures come from Renton's own land use code — confirm them with the city before you design.