ADU rules in Redmond, WA — also called accessory dwelling unit regulations or granny flat ordinances — cover setbacks, owner-occupancy, parking, and permit requirements.
Redmond allows one attached and one detached ADU per single-family lot under RMC 21.08 and WA HB 1337, with no owner-occupancy requirement and streamlined permitting for units up to 1,000 sq ft.
Redmond updated its Accessory Dwelling Unit regulations in 2024 to comply with Washington HB 1337, which requires cities to allow two ADUs per lot in residential zones within urban growth areas. Under RMC 21.08, a single-family lot in Redmond may have one attached ADU and one detached ADU (or two attached ADUs), for up to three dwelling units total on one lot. ADUs may be up to 1,000 square feet of gross floor area, and for detached units height limits match the primary accessory structure limits in the zone. HB 1337 and Redmond implementation removed owner-occupancy requirements, eliminated minimum lot size thresholds beyond the underlying zone, and capped off-street parking requirements at one space per ADU (waived near transit). Short-term rentals (under 30 days) of ADUs are regulated separately under Redmonds short-term rental licensing rules. Design standards align architecture with the primary home, and ADUs must meet building, fire, and utility connection standards.
Contact your local code enforcement office for specific penalty information.
Redmond, WA
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Redmond, WA
Industrial-source noise received in Redmond residential areas may not exceed 60 dBA daytime and 50 dBA nighttime under RMC 6.32 and WAC 173-60. Overlake and ...
Redmond, WA
Redmond generally allows overnight residential street parking within the 72-hour continuous-parking limit. Downtown time zones, snow events, and posted no-pa...
Redmond, WA
Redmond restricts on-street RV and boat parking to 72 hours and regulates driveway storage under RMC Title 21. Many zones limit the number of recreational ve...
Redmond, WA
Redmond regulates driveway width, surfacing, and apron construction under RMC Title 21 and Public Works standards. Residential driveways are typically 10-24 ...
Redmond, WA
Standard residential fences up to 6 feet in side and rear yards and 4 feet in front yards do not require a building permit in Redmond. Permits are needed for...
Side-by-side rule comparisons with other cities in King County.
See how other cities in King County handle adu rules.
See how Redmond's adu rules rules stack up against other locations.
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