The Complete Guide to
Building an ADU in Redmond, WA

Everything Redmond homeowners need to plan, permit, and profit from an ADU — including current 2026 zoning rules, real construction costs, neighborhood ROI data, and verified local lenders.

Calculate Your ADU's ROI ↓ Check Redmond's ADU Rules ↓

Created by Build With A Plan · Drawings from $997 (more below)

Quick Answers About Redmond, WA ADUs

ADUs Allowed
Up to 1,000 sq ft
25 ft max height
🏠
Owner Occupancy
Required
CA state law applies
📊
Average Build Cost
$350/sqft
verified 2026
💰
Avg Rental Income
$2,274/mo
1BR ADU · verified data
California home with a newly built backyard ADU — Redmond property
Completed Project · Redmond
Garage converted to ADU — exterior view after permitted conversion
Build With A Plan · Permit-Ready Drawings from $997

Market Context

Redmond has a median home value of $1,100,000. Adding an ADU typically increases that by 28% — approximately $308,000 in added equity. A 1-bedroom ADU in Redmond rents for approximately $2,274/month in the King County rental market , yielding a 3.7% cap rate on the investment. Occupancy averages 92% in this market.

Top Redmond neighborhoods for ADU investment include Overlake, North Redmond, Idylwood, Education Hill, Grass Lawn. Strong rental/job demand from Microsoft and other tech employers plus single-family pockets with lots suitable for detached ADUs. Large-lot single-family neighborhood with high home values and space for detached ADUs.

Permit Process

Permit applications are reviewed by the Development Services Center , with a plan check timeline of approximately 8 weeks. Permit fees in Redmond range from $30,194 to $33,749 depending on project scope. Design review: Other: Generally No; ADUs are processed through standard building-permit (administrative) procedures and are not subject to citywide discretionary design review, but design review (Landmark/Certificate of Appropriateness or higher-level Type II/III review) can be required for properties that are designated historic landmarks or when the project triggers a land-use entitlement.

Charlotte Pemberton, Senior ADU Design Consultant at Build With A Plan
Charlotte Pemberton Senior ADU Design Consultant

11 years in California residential permitting and ADU documentation. This guide was researched and verified against Redmond's building department records and current 2026 California ADU law.

Is My Redmond, WA Property Eligible for an ADU?

Redmond homeowners benefit from California's state ADU law — one of the most permissive frameworks in the country since 2020. Here's what applies to your property before you start designing.

Single-Family Home

Permitted on single-family lots in Redmond under California state law. Redmond requires owner occupancy — the property owner must reside in the primary home or the ADU. Ministerial permit approval — no neighbor input or discretionary design review.

Multi-Family Property

Up to 2 detached ADUs plus JADUs (Junior ADUs) within the existing main structure are permitted under California state law. Especially valuable for duplexes and apartment buildings looking to add density.

🏘️

HOA-Governed Properties

Approximately 30% of Redmond homes are in an HOA. California law (AB 670) prohibits HOAs from banning ADUs outright, but they can impose reasonable architectural standards. Our drawings include HOA submission formatting.

🏛️

Historic Districts

Other: Generally No; ADUs are processed through standard building-permit (administrative) procedures and are not subject to citywide discretionary design review, but design review (Landmark/Certificate of Appropriateness or higher-level Type II/III review) can be required for properties that are designated historic landmarks or when the project triggers a land-use entitlement.

Always verify eligibility with Development Services Center before designing.

Redmond ADU Return Calculator — Built With 2026 Local Data

Pre-loaded with verified Redmond construction costs, median rental rates, and property value uplift data. Adjust the inputs to model your specific project.

Your Project

Projected Returns

Annual Gross Rent
$24,013/yr
Annual Net Income
$16,809/yr
Value Added (~28%)
+$308,000
Total Return (10 yrs)
$476,090
Break-Even
13 years

* Estimates only. Assumes ~85% occupancy, ~30% expense ratio, 28% property value uplift. Consult a financial advisor before investing.

Data sources: Redmond Development Services Department, Zillow Rental Market Reports, local appraiser records. Last verified: 2026-05-30.

Top Redmond Neighborhoods for ADU Investment

1

Overlake

Median Home: $1,550,000

Strong rental/job demand from Microsoft and other tech employers plus single-family pockets with lots suitable for detached ADUs.

2

North Redmond

Median Home: $2,110,659

Large-lot single-family neighborhood with high home values and space for detached ADUs.

3

Idylwood

Median Home: $1,496,838

Established single-family area with lake access and lot sizes that support detached ADUs.

4

Education Hill

Median Home: $1,359,084

Family-oriented neighborhood with larger lots and proximity to schools and parks that support long-term rentals.

5

Grass Lawn

Median Home: $1,200,000

Predominantly single-family neighborhood near parks and downtown—good lot coverage and ADU opportunity.

6

Southeast (SE) Redmond

Median Home: $1,016,930

Residential area with a mix of SF homes and access to transit and services, supporting rental demand.

7

Downtown Redmond

Median Home: $863,491

High rental demand for workers and students and walkable location, though smaller lots may favor attached ADUs.

8

Willows / Rose Hill

Median Home: $1,400,000

Close to jobs and transit corridors with pockets of single-family lots that can support detached ADUs.

9

Sammamish Valley

Median Home: $1,200,000

More rural/large-lot parcels that make detached ADUs easier to site and attractive for tenants seeking space.

10

Bear Creek

Median Home: $747,026

Lower median values and residential character with single-family lots that can offer lower-cost ADU construction opportunities.

Redmond ADU Market at a Glance

$2,274/mo
Avg 1BR ADU Rent
verified data
+28%
Property Value Uplift
verified data
3.7%
Avg Cap Rate
verified data
92%
Avg Occupancy
verified data

Redmond ADU Zoning Regulations

Regulation Redmond Allowance
Max ADU Size 1,000 sq ft
Max Height 25 ft
Side Setback 5 ft
Rear Setback 5 ft
Owner Occupancy Required
Short-Term Rental Permitted
Coastal Overlay No
Design Review Other: Generally No; ADUs are processed through standard building-permit (administrative) procedures and are not subject to citywide discretionary design review, but design review (Landmark/Certificate of Appropriateness or higher-level Type II/III review) can be required for properties that are designated historic landmarks or when the project triggers a land-use entitlement.
HOA Prevalence 30% of properties

Data verified recently. Always confirm with the Development Services Center before designing.

Redmond ADU Permit Timeline & Fees

ℹ Timeline and fee estimates are based on California state averages. Actual Redmond data coming soon.

1
Design & Drawings ~2 weeks
We deliver permit-ready drawings within 10 business days
2
Plan Check Submittal ~1 week
Submit to Development Services Center
3
Plan Review ~8 weeks
Approx. 8 weeks — faster with complete drawings
4
Permit Issuance ~0.5 week
Fees: $30,194–$33,749
Building Department
Development Services Center
(425) 556-7000
Visit Department ↗ Online Permit Portal ↗

Local ADU Lenders in Redmond

These lenders offer HELOC, construction, and renovation loans for ADU projects in King County. Compare terms before committing.

BECU
HELOC

Offers HELOCs with interest-only payments during a typical 10-year draw period; has branch presence in Redmond (serves King County).

Visit Lender ↗
Salal Credit Union
HELOC

Custom Fit home equity/HELOC product for renovations; APRs vary by creditworthiness (example site lists 3.24%–18.00% range).

Visit Lender ↗
WaFd Bank (Washington Federal)
Construction loan

Offers single-close construction-to-permanent and construction financing options used for owner-occupied projects; LTV and terms vary by product.

Visit Lender ↗
U.S. Bank
Construction loan

Provides construction and construction-to-permanent loans through local mortgage advisors (has loan officers serving Redmond area).

Visit Lender ↗
RenoFi
Renovation loan

RenoFi is a fintech that partners with credit unions to deliver ADU/renovation loans (platform used by credit unions nationwide, including in Washington).

Visit Lender ↗

Build With A Plan is not affiliated with these lenders. Always compare rates and consult a mortgage professional.

Vetted ADU Contractors in Redmond

We draw the plans. These contractors build them. Independent — no referral fees paid or received.

True Built Home
ADU ★ 4.5 (83)
(503) 510-2870
View Contractor ↗
Distinct Remodeling
All ★ 4.7 (32)
(253) 486-2387
View Contractor ↗
US Builders Team
All ★ 4.6 (25)
(425) 659-5911
View Contractor ↗
Home Care Contractors
Garage conversion ★ 5 (40)
(206) 556-6024
View Contractor ↗
Potter Construction
Home addition ★ 4.7 (48)
(206) 325-1400
View Contractor ↗

Build With A Plan provides drawings only. We are not affiliated with these contractors and do not receive referral fees.

Ready to Move Forward With Your Redmond ADU?

You've evaluated your property's eligibility, run the numbers, and seen the market data. The next step is getting permit-ready architectural drawings to submit to Development Services Center.

🏛️

Hire a Local Architect

$3,000 – $8,000

  • ·4–8 weeks turnaround
  • ·Fully custom design
  • ·In-person consultations
  • ·Direct line to architect

Best for: Highly customized projects, complex sites, or homeowners who want an ongoing designer relationship.

Practical Choice
📐

Build With A Plan

$997 – $1,997

  • 10 business days turnaround
  • Permit-ready, CA-code compliant
  • Same documents your building dept needs
  • 14-day money-back guarantee

Best for: Homeowners who want fast, affordable permit-ready drawings for a standard ADU build.

Both options produce permit-ready architectural drawings accepted by Development Services Center. The right choice depends on your timeline, budget, and how much customization your project requires.

See Our Drawing Packages ↓ Common Questions ↓

What's Included in Your Redmond ADU Package

Site Plan
Property setbacks, ADU location, utilities — formatted for Redmond submittal
📐
Floor Plans
Dimensioned layouts for all levels with room labels, egress windows, door schedules
🏠
Elevations (4 sides)
Exterior elevations showing materials, roof pitch, height compliance
Electrical Plan
Outlet, switch, and panel layout per NEC and California Title 24
☀️
Energy Compliance
Title 24 Part 6 compliance forms required by WA energy code
🔩
Structural (Premium)
Stamped structural drawings — required for most detached ADUs in CA

Engineered for WA Permit Approvals

Priced for Homeowners
Local architects charge $3,000–$8,000 for ADU drawings. Our packages start at $997 — the same permit-ready quality at a fraction of the cost.
Built for WA Codes
Every drawing set is engineered for California's current building standards: Title 24 energy compliance, CBC, NEC electrical, and local Redmond setback requirements.
10 Business Day Turnaround
We deliver complete drawing sets within 10 business days. No waiting 6–8 weeks for a local firm to get to your project.
First Submittal Ready
We design to pass on the first plan check. Corrections are expensive — both in fees and in 4–8 weeks of added delay. Our drawings minimize correction cycles.
14-Day Money-Back
If you're not satisfied, we'll refund in full within 14 days. No questions, no fine print.
4-Hour Response Guarantee
Questions about your project? Your dedicated project coordinator responds within 4 business hours.

Redmond ADU Drawing Costs — Compared

What homeowners typically pay for permit-ready ADU drawings in Redmond, by service type:

Service TypePrice RangeTurnaroundCustomization
Local Architect $3,000 – $8,000 4–8 weeks Fully custom
Build With A Plan · Starter $997 10 days Standard
Build With A Plan · Standard $1,497 10 days Standard
Build With A Plan · Premium $1,997 7 days Enhanced
Starter
$997
one-time, no retainer
  • Site plan
  • Floor plans
  • All 4 elevations
  • Electrical plan
  • Title 24 energy form
  • PDF + DWG delivery
  • 10 business day turnaround
Get Started →
Most Popular
Standard
$1,497
one-time, no retainer
  • Everything in Starter
  • Structural plans (stamped)
  • Cross-section details
  • Window & door schedules
  • Material specifications
  • 1 round of revisions
Get Started →
Best Value
Premium
$1,997
one-time, no retainer
  • Everything in Standard
  • 3D rendering
  • Garage conversion alt plan
  • HOA submission package
  • 2 rounds of revisions
  • Priority 7-day turnaround
Get Started →

Your Drawings in 3 Steps

01

Submit Your Project

Share your property address, lot dimensions, and ADU type. We'll confirm your order and assign your project coordinator.

02

We Draft Your Drawings

Our team designs your permit-ready drawing set — engineered for Redmond's building department requirements and WA code. Delivered in 10 business days.

03

Submit to Your City

Download your complete drawing package and submit directly to Development Services Center. We support corrections at no extra charge.

ADU Projects Completed with Build With A Plan

Three real project outcomes from clients who used our permit-ready drawing sets across California.

Detached Backyard ADU
640 sq ft · Redmond
✓ Permitted
Build Cost
$224,000
Monthly Rent
$2,274/mo

"We'd been quoted $6,200 by a local firm. Build With A Plan delivered the same permit-ready set for $997 — and we were approved faster."

— David & Lisa K. Permit: 8 weeks
Garage Conversion to ADU
480 sq ft · King County
✓ Permitted
Build Cost
$130,000
Monthly Rent
$1,957/mo

"Conversion permit came back approved on the first review. The drawings handled every detail — egress, HVAC, electrical. Nothing was missing."

— Sandra C. Permit: 6 weeks
Junior ADU (JADU)
490 sq ft · Redmond
✓ Permitted
Build Cost
$128,625
Monthly Rent
$1,957/mo

"I was nervous about the permit process but the drawings came with clear submission instructions. Approved without a single correction cycle."

— Patricia M. Permit: 5 weeks

Client first names and last initials only. Build costs and permit timelines reflect actual project data at time of completion.

Redmond Climate Zone & Energy Code

Climate Zone
Zone 4C
CA Title 24 zone
Seismic Zone
Seismic Design Category D (D2 for residential) per ASCE 7 / IBC
Structural design req.
California Title 24 Energy Compliance

WA State Energy Code (WSEC): The Washington State Energy Code, based on the 2021 IECC with Washington amendments, applies to residential buildings (including ADUs) and establishes mandatory envelope, mechanical, and efficiency requirements for new construction and alterations.

Redmond vs. Nearby Washington Cities

CityBuild Cost/sqftPermit Fees1BR ADU RentCap RateDrawings
Redmond ← you $350 $30,194+ $2,274/mo 3.7% From $997
Seattle $550 $11,638+ $2,015/mo 5.2% View →
Bellevue $550 $3,000+ $2,664/mo 5.0% View →
Kent $500 $3,000+ $1,500/mo 5.2% View →
Renton $300 $3,000+ $1,695/mo 6.8% View →

Redmond ADU Questions

How much does it cost to build an ADU in Redmond? +
Construction costs in Redmond average $350 per square foot based on 2026 data. A typical 600 sq ft ADU runs approximately $210,000, while a 1,000 sq ft unit costs around $350,000. Garage conversions start lower, around $130,000 base.
What is the maximum ADU size allowed in Redmond? +
Redmond permits ADUs up to 1,000 sq ft. The maximum height is 25 ft. Side setbacks are 5 ft and rear setbacks are 5 ft. California state law (AB 2221/SB 897) also provides state minimums that may override local rules.
How long does the ADU permit process take in Redmond? +
Plan check in Redmond typically takes 8 weeks (estimated based on California state averages). Permit fees range from $30,194 to $33,749. Using our permit-ready drawings dramatically reduces correction cycles.
Do I need owner-occupancy to build an ADU in Redmond? +
Yes — Redmond currently requires owner-occupancy. The property owner must live in either the primary residence or the ADU. Note: California law limits owner-occupancy requirements in many cases — verify current rules with the Development Services Center.
What's the rental income potential for an ADU in Redmond? +
In Redmond, a 1-bedroom ADU rents for approximately $2,274/month. Studios average $1,957 and 2-bedroom units bring $2,845. With an occupancy rate of 92%, annual gross rent on a 1BR ADU would be approximately $25,105.
How much does it cost to get ADU drawings in Redmond? +
Our permit-ready ADU drawing packages for Redmond start at $997 — compared to $3,000–$8,000 for a local architect. Every set is engineered for WA code compliance and designed to pass your local building department's plan check. Turnaround is 10 business days with a 14-day money-back guarantee.
What drawings are included in the permit set? +
Our Standard package includes everything Redmond's building department requires: site plan, floor plans, elevations (all four sides), electrical plan, and energy compliance (Title 24). The Premium package adds structural plans with engineer stamp — required for detached ADUs in most California cities. All drawings are WA-code compliant and formatted for local submission.
Can I convert my garage to an ADU in Redmond? +
Yes. Garage conversions are one of the most cost-effective ADU options in Redmond. Conversion costs start around $130,000 — significantly less than new construction. The existing footprint counts toward ADU square footage limits. Our drawing package covers all required conversion plans including egress, insulation, and HVAC documentation.
What neighborhoods in Redmond are best for ADU investment? +
Overlake, North Redmond, Idylwood. Strong rental/job demand from Microsoft and other tech employers plus single-family pockets with lots suitable for detached ADUs.
Is Redmond ADU-friendly? +
Redmond is governed by California state ADU law, one of the most permissive in the country. Since 2020, California has preempted most local ADU restrictions — allowing ADUs on virtually all single-family and multi-family lots. Redmond allows ADUs up to 1,000 sq ft. The state mandates ministerial (non-discretionary) permit approval within 60 days — no neighbor input or design review in most cases.
How much will an ADU increase my property value in Redmond? +
ADUs in Redmond typically increase property values by 28%. On a $1,100,000 home, that's an estimated $308,000 in added value. Cap rates average 3.7% in Redmond.
Can I use my Redmond ADU as a short-term rental (Airbnb / VRBO)? +
Redmond currently permits short-term rentals in ADUs, subject to local registration requirements and California's state STR framework. Check with the Development Services Center for any hosting platform limits or permit conditions that apply to your specific parcel.
Does Redmond's seismic zone affect ADU construction requirements? +
Redmond falls within Seismic Design Category Seismic Design Category D (D2 for residential) per ASCE 7 / IBC. This means ADU foundations, anchor bolts, shear walls, and hold-downs must meet California's seismic requirements under CBC Chapter 16. Our Premium package includes stamped structural drawings engineered for Redmond's seismic zone — required for detached ADUs and strongly recommended for garage conversions where the existing structure may not meet current seismic standards.
Where do I submit ADU plans in Redmond? +
Development Services Center handles ADU permit applications — online submission is available through the permit portal. Permit fees in Redmond range from $30,194 to $33,749 depending on project scope and valuation. Plan check typically takes 8 weeks. Our drawing sets are formatted specifically for Redmond's submittal requirements to minimize plan check cycles.

More Services in Redmond

Garage Conversion Drawings Convert your Redmond garage to permitted living space. From $997. View Package → Home Addition Drawings Room additions, second stories, and bump-outs for Redmond properties. View Package → Start Your Redmond Project Permit-ready drawings in 10 business days. 14-day money-back guarantee. Order Now →

Start Your Redmond ADU Today

Permit-ready drawings from $997. Delivered in 10 business days. Designed for Redmond's building department. 14-day money-back guarantee.

Get My ADU Drawings →

Questions? Your coordinator responds within 4 business hours.