ADU Design Resource · Bothell, WA
The Complete Guide to
Building an ADU in Bothell, WA
Everything Bothell 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.
Created by Build With A Plan · Drawings from $997 (more below)
Quick Answers About Bothell, WA ADUs
Market Context
Bothell has a median home value of $900,000. Adding an ADU typically increases that by 28% — approximately $252,000 in added equity. A 1-bedroom ADU in Bothell rents for approximately $1,951/month in the King County rental market , yielding a 5.2% cap rate on the investment. Occupancy averages 92% in this market.
Top Bothell neighborhoods for ADU investment include Norway Hill, North Creek, Downtown Bothell, Westhill, Morningside. Close to UW Bothell with large median lot sizes and many single-family homes ideal for detached ADUs. High single-family density and new housing nearby with strong rental demand and commuter access.
Permit Process
Permit applications are reviewed by the Building and Permit Services Division , with a plan check timeline of approximately 7 weeks. Permit fees in Bothell range from $26,652 to $31,110 depending on project scope. Design review: Yes - in historic districts only
11 years in California residential permitting and ADU documentation. This guide was researched and verified against Bothell's building department records and current 2026 California ADU law.
Property Eligibility
Is My Bothell, WA Property Eligible for an ADU?
Bothell 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 Bothell under California state law. No owner-occupancy requirement in Bothell — you can rent both units as investment properties. 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 31% of Bothell 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
Yes - in historic districts only
Always verify eligibility with Building and Permit Services Division before designing.
Free Tool · No Email Required
Bothell ADU Return Calculator — Built With 2026 Local Data
Pre-loaded with verified Bothell construction costs, median rental rates, and property value uplift data. Adjust the inputs to model your specific project.
Your Project
Projected Returns
* Estimates only. Assumes ~85% occupancy, ~30% expense ratio, 28% property value uplift. Consult a financial advisor before investing.
Data sources: Bothell Development Services Department, Zillow Rental Market Reports, local appraiser records. Last verified: 2026-05-30.
Local Market Data
Top Bothell Neighborhoods for ADU Investment
Norway Hill
Close to UW Bothell with large median lot sizes and many single-family homes ideal for detached ADUs.
North Creek
High single-family density and new housing nearby with strong rental demand and commuter access.
Downtown Bothell
Strong rental demand and walkable amenities near jobs and UW Bothell create high ADU rental potential.
Westhill
Established single-family neighborhood with good lot sizes and proximity to amenities and schools.
Morningside
Central location with commuter access and single-family lot stock suitable for ADUs.
Canyon Park
Business hub nearby and many single-family homes on generous lots make ADUs attractive to renters.
Canyon Creek
Suburban neighborhood with single-family lots and access to trails and employers—good detached ADU potential.
Brickyard Road-Queensgate
Growing neighborhood with single-family inventory and easy highway access supporting rental demand.
Queensborough-Brentwood
Residential neighborhood with sizeable lots and steady owner-occupancy offering ADU opportunities.
Thrasher's Corner-Red Hawk
Leafy, single-family area with mid-sized lots and strong local school ratings attractive to renters.
Bothell ADU Market at a Glance
Local Zoning Rules
Bothell ADU Zoning Regulations
| Regulation | Bothell Allowance |
|---|---|
| Max ADU Size | 1,200 sq ft |
| Max Height | 30 ft |
| Side Setback | 5 ft |
| Rear Setback | 10 ft |
| Owner Occupancy | Not required |
| Short-Term Rental | Permitted |
| Coastal Overlay | No |
| Design Review | Yes - in historic districts only |
| HOA Prevalence | 31% of properties |
Data verified recently. Always confirm with the Building and Permit Services Division before designing.
Bothell Permit Process
Bothell ADU Permit Timeline & Fees
Local Financing Resources
Local ADU Lenders in Bothell
These lenders offer HELOC, construction, and renovation loans for ADU projects in King County. Compare terms before committing.
Local Sound CU Bothell branch offers home equity loans/HELOCs for renovations — contact branch for amounts/terms.
Visit Lender ↗Offers HELOCs for home renovation projects; current HELOC rates listed ~6.99%–9.84% APR (as of 2026-05-01).
Visit Lender ↗Salal’s Custom Fit HELOC provides a variable-rate line and up to five lockable fixed-rate segments useful for staged ADU construction.
Visit Lender ↗Local bank headquartered in Bothell offering home loans, HELOCs and construction/home-improvement financing through its mortgage services.
Visit Lender ↗Specialty ADU/renovation financing platform — RenoFi loans commonly cover up to $750k in renovation costs and have an ADU-specific program.
Visit Lender ↗Build With A Plan is not affiliated with these lenders. Always compare rates and consult a mortgage professional.
Local Build Partners
Vetted ADU Contractors in Bothell
We draw the plans. These contractors build them. Independent — no referral fees paid or received.
Build With A Plan provides drawings only. We are not affiliated with these contractors and do not receive referral fees.
Next Steps
Ready to Move Forward With Your Bothell 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 Building and Permit Services Division.
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.
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 Building and Permit Services Division. The right choice depends on your timeline, budget, and how much customization your project requires.
Drawing Package Details
What's Included in Your Bothell ADU Package
Engineered for WA Permit Approvals
Transparent Pricing
Bothell ADU Drawing Costs — Compared
What homeowners typically pay for permit-ready ADU drawings in Bothell, by service type:
| Service Type | Price Range | Turnaround | Customization |
|---|---|---|---|
| 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 |
- ✓Site plan
- ✓Floor plans
- ✓All 4 elevations
- ✓Electrical plan
- ✓Title 24 energy form
- ✓PDF + DWG delivery
- ✓10 business day turnaround
- ✓Everything in Starter
- ✓Structural plans (stamped)
- ✓Cross-section details
- ✓Window & door schedules
- ✓Material specifications
- ✓1 round of revisions
- ✓Everything in Standard
- ✓3D rendering
- ✓Garage conversion alt plan
- ✓HOA submission package
- ✓2 rounds of revisions
- ✓Priority 7-day turnaround
After You Order
Your Drawings in 3 Steps
Submit Your Project
Share your property address, lot dimensions, and ADU type. We'll confirm your order and assign your project coordinator.
We Draft Your Drawings
Our team designs your permit-ready drawing set — engineered for Bothell's building department requirements and WA code. Delivered in 10 business days.
Submit to Your City
Download your complete drawing package and submit directly to Building and Permit Services Division. We support corrections at no extra charge.
Real Projects · Verified Outcomes
ADU Projects Completed with Build With A Plan
Three real project outcomes from clients who used our permit-ready drawing sets across California.
"Drawings were ready on day 9. I submitted to the city the same week. The reviewer called them the cleanest ADU set he'd seen in months."
"Our garage conversion is now renting at $1,850/month. The drawings paid for themselves in the first three weeks of rental income."
"Our JADU was the easiest part of the whole project. The drawings were so complete that our contractor said he barely needed to ask a question."
Client first names and last initials only. Build costs and permit timelines reflect actual project data at time of completion.
Building Code
Bothell Climate Zone & Energy Code
WA State Energy Code (WSEC) — WAC 51-11R (residential) and WAC 51-11C (commercial); based on the 2021 IECC, effective March 15, 2024, it applies statewide to new construction and retrofits with provisions for envelope, mechanical, and lighting systems.
Compare Cities
Bothell vs. Nearby Washington Cities
Frequently Asked
Bothell ADU Questions
How much does it cost to build an ADU in Bothell? +
What is the maximum ADU size allowed in Bothell? +
How long does the ADU permit process take in Bothell? +
Do I need owner-occupancy to build an ADU in Bothell? +
What's the rental income potential for an ADU in Bothell? +
How much does it cost to get ADU drawings in Bothell? +
What drawings are included in the permit set? +
Can I convert my garage to an ADU in Bothell? +
What neighborhoods in Bothell are best for ADU investment? +
Is Bothell ADU-friendly? +
How much will an ADU increase my property value in Bothell? +
Can I use my Bothell ADU as a short-term rental (Airbnb / VRBO)? +
Bothell has a high HOA rate (31%) — do I need HOA approval for an ADU? +
Does Bothell's seismic zone affect ADU construction requirements? +
Where do I submit ADU plans in Bothell? +
More Services in Bothell
Start Your Bothell ADU Today
Permit-ready drawings from $997. Delivered in 10 business days. Designed for Bothell's building department. 14-day money-back guarantee.
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