Can I build a backyard home in Redmond?
Since 2023, Washington law lets most city lots hold up to two more homes. Redmond writes its own rules on top. Here’s what the code says, in plain English — and a free report on what may fit on your lot.
What Redmond allows.
The headline standards. Open any card for the full wording and the code section.
ADUs per lot2 per lotFull wording
2 per lot — 'Two ADUs or tiny homes shall be allowed on each residential lot' (RZC 21.04.1110.C.1). NR zone also caps total dwelling units per lot at 6 (8 with one affordable unit), Table 21.08.200.B
Max size1,000 sq ftFull wording
1,000 sq ft — 'The total square footage of an ADU shall not exceed 1,000 square feet' (RZC 21.04.1110.C.3.a). Administrator may allow more on lots over 10,000 sq ft only if the unit is affordable or provides a public benefit (C.3.c). Accessory-structure footprint capped at 60 percent of the primary home's ground-floor living area excluding garage (RZC 21.04.1120.C.2.a). Whole-lot gross floor area cap in NR: 4,500 sq ft with 1 unit, 6,000 with 2, 7,500 with 3 (Table 21.08.200.C)
Max height38 ft (the NR zone maximum)Full wording
38 ft — accessory structures containing an ADU may go to the NR zone maximum of 38 ft (RZC 21.04.1120.C.1; Table 21.08.200.B); other accessory structures 22 ft
Front setback10 ft minimum in NRFull wording
10 ft minimum in NR (Table 21.08.300.A); accessory structures are prohibited within the front yard setback (RZC 21.04.1120.C.4)
Side setback3 ft interior side, 10 ft street side in NRFull wording
3 ft interior side, 10 ft street side in NR (Table 21.08.300.A); 5 ft minimum building separation
Rear setback5 ft in NRFull wording
5 ft in NR (Table 21.08.300.A); 2 ft from an alley; a detached ADU may sit on a lot line that abuts a public alley or right-of-way (RZC 21.04.1110.C.2.b)
Lot coverage50% of lot area (NR); impervious 70%Full wording
50 % of lot area for structures in NR (60 % only on lots of 18,000 sq ft or less with 3 or more units); maximum impervious surface 70 %; minimum open space 20 % (Table 21.08.200.B)
ParkingNoneFull wording
None — 0 spaces required for an accessory dwelling unit in every location category (Table 21.40.010D, Ord. 3261)
Where a city figure reads stricter than the state floor (RCW 36.70A.681), the floor may control — the report flags it for your parcel.
Living there, selling it, plans, time and fees.
Each answer is the code’s own wording, with the section it comes from. “Not published yet” means the city hasn’t posted a figure — the report asks the city, not the internet.
Are backyard homes allowed?
Yes — accessory dwelling units are a permitted use (P) in the NR, NMF, NMU, CMU, MME, DTE, DTC, TWNC, UR and RA-5 zones; attached or detached (RZC 21.04.0100 use table; RZC 21.04.1110.C.2)
Minimum lot size
None for an ADU — allowed on any residential lot; NR average minimum lot size for new lots is 3,000 sq ft (Table 21.08.200.B)
Do you have to live there?
No — no owner-occupancy requirement in RZC 21.04.1110 (removed; prohibited by RCW 36.70A.681 inside the UGA)
Can it be sold on its own?
Yes — no prohibition on separate ownership in the current RZC 21.04.1110 (the old 'shall not be segregated in ownership' clause is gone); RCW 36.70A.681 requires cities to allow ADU condominiums. Confirm the condominium process with the city and a title company
Pre-approved plans
None found — Redmond had no pre-approved ADU plan program on its website as of 2026-10-01; confirm with Planning
How long the city takes
Not published for ADUs; a detached ADU is a building permit through MyBuildingPermit with planning, tree and utility review. Confirm current turnaround with Development Services
Impact fees
2026 schedule (Ord. 3240) for a single-family detached unit: school $7,277.00 + fire $148.78 + parks $6,914.63 + transportation $10,107.51 = $24,447.92. No ADU line is published; RCW 36.70A.681 caps ADU impact fees at 50 percent of the principal unit, so plan on up to about $12,224 and confirm at permit. Water/sewer connection charges apply separately and depend on the connection
The code is half the answer. Your parcel is the other half.
Lines and easements
Where the lot lines really are, which setbacks apply on each side, and whether a utility or access easement takes the corner you had in mind.
Critical areas and slope
Steep slopes, wetlands and streams come with buffers that no citywide number shows. The report reads the county’s maps for your parcel.
Sewer, septic, water, trees
Whether sewer reaches the lot or it’s on septic, where the water service is, and which trees a city protects — the things that decide where a unit can actually go.
What Redmond allows, what could fit on your lot, and a planning cost range. If something won’t fit, the report says so — and shows what might.
Where this page comes from.
Read from the Redmond municipal code and the city’s own pages on October 1, 2026. The same table feeds the HousUp report, so the report and this page never disagree. Cities amend their codes; before you design anything, confirm the current wording with the city.
- redmond.municipal.codes/RZC/21.04.1110
- redmond.municipal.codes/RZC/21.04.1120
- redmond.municipal.codes/RZC/21.08.200
- redmond.municipal.codes/RZC/21.08.300
- redmond.municipal.codes/RZC/21.40.010
- redmond.municipal.codes/RZC/21.72.060
- www.redmond.gov/DocumentCenter/View/40265/2026-Impact-Fees-Schedule---adopted-by-Ord-3240
- RCW 36.70A.681 — the state floor for accessory dwelling units
Find out what your property could become.
Type your address. Within a few hours: what Redmond allows, what could fit, and a planning cost range. Free, no obligation.