The Complete Guide to
Building an ADU in Lake Stevens, WA

Everything Lake Stevens 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 Lake Stevens's ADU Rules ↓

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

Quick Answers About Lake Stevens, WA ADUs

ADUs Allowed
Up to 1,000 sq ft
35 ft max height
🏠
Owner Occupancy
Not required
CA state law applies
📊
Average Build Cost
$300/sqft
verified 2026
💰
Avg Rental Income
$1,450/mo
1BR ADU · verified data
Modern detached ADU in a California backyard — completed project in Lake Stevens
Completed Project · Lake Stevens
Interior of a permitted ADU studio unit — open-plan living and kitchen
Build With A Plan · Permit-Ready Drawings from $997

Market Context

Lake Stevens has a median home value of $570,000. Adding an ADU typically increases that by 28% — approximately $159,600 in added equity. A 1-bedroom ADU in Lake Stevens rents for approximately $1,450/month in the Snohomish County rental market , yielding a 5.2% cap rate on the investment. Occupancy averages 92% in this market.

Top Lake Stevens neighborhoods for ADU investment include Getchell, Lake Cassidy, Lochsloy, South Lake Stevens, Cavalero. High median values and larger lot sizes provide the equity and space needed for detached ADU construction. Large lot sizes and high property values make this an ideal area for high-end rental ADUs.

Permit Process

Permit applications are reviewed by the Planning & Community Development department , with a plan check timeline of approximately 8 weeks. Permit fees in Lake Stevens range from $7,997 to $10,643 depending on project scope. Design review: No - only required for housing developments/subdivisions or projects within adopted subareas; individual ADUs are exempt.

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 Lake Stevens's building department records and current 2026 California ADU law.

Is My Lake Stevens, WA Property Eligible for an ADU?

Lake Stevens 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 Lake Stevens under California state law. No owner-occupancy requirement in Lake Stevens — 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 30% of Lake Stevens 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.

Always verify eligibility with Planning & Community Development department before designing.

Lake Stevens ADU Return Calculator — Built With 2026 Local Data

Pre-loaded with verified Lake Stevens 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
$15,312/yr
Annual Net Income
$10,718/yr
Value Added (~28%)
+$159,600
Total Return (10 yrs)
$266,780
Break-Even
17 years

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

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

Top Lake Stevens Neighborhoods for ADU Investment

1

Getchell

Median Home: $1,186,000

High median values and larger lot sizes provide the equity and space needed for detached ADU construction.

2

Lake Cassidy

Median Home: $902,625

Large lot sizes and high property values make this an ideal area for high-end rental ADUs.

3

Lochsloy

Median Home: $867,500

Strong residential character with sufficient lot sizes supports detached accessory units.

4

South Lake Stevens

Median Home: $795,000

Proximity to the lake and high demand for housing makes this a prime location for rental ADUs.

5

Cavalero

Median Home: $772,475

Strategic location near transit corridors creates high demand for additional housing units.

6

Cavalero Hill

Median Home: $710,000

Consistent residential growth and stable home values support long-term ADU investment.

7

Downtown / Central Lake Stevens

Median Home: $668,000

Established single-family density provides numerous opportunities for backyard cottage development.

8

North Lake Stevens

Median Home: $655,000

Larger suburban lots in this area are well-suited for detached ADU structures.

9

West Lake Stevens

Median Home: $640,000

High density of single-family homes makes it a target for internal or attached ADU conversions.

10

Soper Hill

Median Home: $625,000

Affordable entry points for homeowners looking to add value through ADU development.

Lake Stevens ADU Market at a Glance

$1,450/mo
Avg 1BR ADU Rent
verified data
+28%
Property Value Uplift
verified data
5.2%
Avg Cap Rate
verified data
92%
Avg Occupancy
verified data

Lake Stevens ADU Zoning Regulations

Regulation Lake Stevens Allowance
Max ADU Size 1,000 sq ft
Max Height 35 ft
Side Setback 5 ft
Rear Setback 10 ft
Owner Occupancy Not required
Short-Term Rental Permitted
Coastal Overlay No
Design Review No - only required for housing developments/subdivisions or projects within adopted subareas; individual ADUs are exempt.
HOA Prevalence 30% of properties

Data verified recently. Always confirm with the Planning & Community Development department before designing.

Lake Stevens ADU Permit Timeline & Fees

ℹ Timeline and fee estimates are based on California state averages. Actual Lake Stevens 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 Planning & Community Development department
3
Plan Review ~8 weeks
Approx. 8 weeks — faster with complete drawings
4
Permit Issuance ~0.5 week
Fees: $7,997–$10,643
Building Department
Planning & Community Development department
(425) 622-9400
Visit Department ↗ Online Permit Portal ↗

Local ADU Lenders in Lake Stevens

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

WSECU
HELOC

Offers home equity loans and HELOCs up to ~90% LTV; advertised HELOC rate range ~6.49%–9.50%; membership required.

Visit Lender ↗
BECU
HELOC

Provides HELOCs (rates cited ~6.99%–9.84% APR as of 2026-05-01) and construction loans (construction financing up to multi-million amounts and LTVs commonly 75%–80%).

Visit Lender ↗
Heritage Bank
HELOC

Local Washington bank with a Lake Stevens branch offering HELOCs for home improvements and renovations.

Visit Lender ↗
Columbia Bank
Construction loan

Regional bank offering construction-to-permanent loans for new builds and renovations — suitable for ADU construction or major remodels.

Visit Lender ↗
RenoFi
Renovation loan

Specialty renovation lender partnering with credit unions; loan amounts cited $10k–$750k and offers products up to ~90% of after-renovation value.

Visit Lender ↗

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

Vetted ADU Contractors in Lake Stevens

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

New Day Construction
All ★ 4.9 (150)
(425) 584-2936
View Contractor ↗
Giant Builders Seattle (Lake Stevens)
All ★ 4.8 (48)
(425) 944-5460
View Contractor ↗
New Property Solutions LLC
All
(425) 923-5550
View Contractor ↗
North Pacific Contractors LLC
All
(707) 720-6239
View Contractor ↗
Emerald Quality Construction LLC
All
(425) 773-6717
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 Lake Stevens 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 Planning & Community Development department.

🏛️

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 Planning & Community Development department. 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 Lake Stevens ADU Package

Site Plan
Property setbacks, ADU location, utilities — formatted for Lake Stevens 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 Lake Stevens 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.

Lake Stevens ADU Drawing Costs — Compared

What homeowners typically pay for permit-ready ADU drawings in Lake Stevens, 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 Lake Stevens'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 Planning & Community Development department. 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 · Lake Stevens
✓ Permitted
Build Cost
$192,000
Monthly Rent
$1,450/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 · Snohomish County
✓ Permitted
Build Cost
$116,500
Monthly Rent
$1,195/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 · Lake Stevens
✓ Permitted
Build Cost
$110,250
Monthly Rent
$1,195/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.

Lake Stevens Climate Zone & Energy Code

Climate Zone
Zone 4C
CA Title 24 zone
Seismic Zone
Seismic Design Category D2
Structural design req.
California Title 24 Energy Compliance

WA State Energy Code: The 2021 Washington State Energy Code (WSEC), effective March 15, 2024, adopts the 2021 IECC with Washington amendments and requires energy-efficiency compliance for residential buildings (including one- and two-family dwellings and ADUs) addressing the building envelope, mechanical systems, water heating, and lighting.

Lake Stevens vs. Nearby Washington Cities

CityBuild Cost/sqftPermit Fees1BR ADU RentCap RateDrawings
Lake Stevens ← you $300 $7,997+ $1,450/mo 5.2% From $997
Everett $375 $3,458+ $1,450/mo 6.0% View →
Marysville $320 $3,000+ $1,750/mo 5.2% View →
Edmonds $300 $11,382+ $1,693/mo 5.2% View →
Lynnwood $500 $3,000+ $1,836/mo 3.2% View →

Lake Stevens ADU Questions

How much does it cost to build an ADU in Lake Stevens? +
Construction costs in Lake Stevens average $300 per square foot based on 2026 data. A typical 600 sq ft ADU runs approximately $180,000, while a 1,000 sq ft unit costs around $300,000. Garage conversions start lower, around $116,500 base.
What is the maximum ADU size allowed in Lake Stevens? +
Lake Stevens permits ADUs up to 1,000 sq ft. The maximum height is 35 ft. Side setbacks are 5 ft and rear setbacks are 10 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 Lake Stevens? +
Plan check in Lake Stevens typically takes 8 weeks (estimated based on California state averages). Permit fees range from $7,997 to $10,643. Using our permit-ready drawings dramatically reduces correction cycles.
Do I need owner-occupancy to build an ADU in Lake Stevens? +
No — Lake Stevens does not require owner-occupancy for ADUs. You can rent both the main house and the ADU as investment properties.
What's the rental income potential for an ADU in Lake Stevens? +
In Lake Stevens, a 1-bedroom ADU rents for approximately $1,450/month. Studios average $1,195 and 2-bedroom units bring $1,800. With an occupancy rate of 92%, annual gross rent on a 1BR ADU would be approximately $16,008.
How much does it cost to get ADU drawings in Lake Stevens? +
Our permit-ready ADU drawing packages for Lake Stevens 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 Lake Stevens'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 Lake Stevens? +
Yes. Garage conversions are one of the most cost-effective ADU options in Lake Stevens. Conversion costs start around $116,500 — 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 Lake Stevens are best for ADU investment? +
Getchell, Lake Cassidy, Lochsloy. High median values and larger lot sizes provide the equity and space needed for detached ADU construction.
Is Lake Stevens ADU-friendly? +
Lake Stevens 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. Lake Stevens 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 Lake Stevens? +
ADUs in Lake Stevens typically increase property values by 28%. On a $570,000 home, that's an estimated $159,600 in added value. Cap rates average 5.2% in Lake Stevens.
Can I use my Lake Stevens ADU as a short-term rental (Airbnb / VRBO)? +
Lake Stevens currently permits short-term rentals in ADUs, subject to local registration requirements and California's state STR framework. Check with the Planning & Community Development department for any hosting platform limits or permit conditions that apply to your specific parcel.
Does Lake Stevens's seismic zone affect ADU construction requirements? +
Lake Stevens falls within Seismic Design Category Seismic Design Category D2. 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 Lake Stevens'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 Lake Stevens? +
Planning & Community Development department handles ADU permit applications — online submission is available through the permit portal. Permit fees in Lake Stevens range from $7,997 to $10,643 depending on project scope and valuation. Plan check typically takes 8 weeks. Our drawing sets are formatted specifically for Lake Stevens's submittal requirements to minimize plan check cycles.

More Services in Lake Stevens

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

Start Your Lake Stevens ADU Today

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

Get My ADU Drawings →

Questions? Your coordinator responds within 4 business hours.