Garage ADU guide
The complete guide to converting your Tacoma garage into a rental ADU — permits, costs, and what to expect.
Everything Tacoma homeowners need to know before converting a garage into a permitted accessory dwelling unit — from lot coverage rules and permit timelines to plumbing rough-in and rental income estimates.
A garage-to-ADU conversion is one of the highest-ROI projects a Tacoma homeowner can undertake — adding a legal rental unit to an existing lot without buying land. But the permitting, structural, and utility requirements are more involved than a basic garage finishing job. This guide covers what you need to know before you start.
Section 1 of 4
Eligibility & zoning
Whether your Tacoma property qualifies for a garage ADU conversion.
Does my Tacoma property qualify for a garage ADU?
Most single-family residential parcels in Tacoma are eligible for at least one ADU. Eligibility depends on zoning district, lot size, lot coverage remaining after the ADU footprint, setbacks, and utility connection availability. We run a full feasibility check at the free consultation.
How much of my lot can the ADU cover?
Tacoma's ADU rules specify maximum lot coverage — the combined footprint of the primary dwelling and all accessory structures (including a converted garage) cannot exceed the zoning district's maximum lot coverage percentage. We calculate remaining coverage for your specific parcel before the project is scoped.
Can I have both an ADU and a JADU (junior ADU) on my Tacoma property?
Washington State law allows one ADU and one JADU on a single-family lot. Tacoma's local rules govern the specifics. We advise on the combination that best serves your goals during the consultation.
Section 2 of 4
Permits & process
The Tacoma ADU permitting process from application to Certificate of Occupancy.
What permits does a Tacoma garage-to-ADU conversion require?
Building permit (change of occupancy and structural), electrical permit, plumbing permit, and mechanical permit. Some projects also require a land use review. We prepare and submit all permit applications in-house and manage the plan review and inspection sequence.
How long does the Tacoma ADU permitting process take?
Plan review at the City of Tacoma for an ADU conversion typically runs 6–10 weeks. We submit complete, code-compliant plans to minimize revision cycles. The permitting timeline is built into the written proposal.
What happens at the final inspection?
A City of Tacoma building inspector reviews all completed work — structure, electrical, plumbing, mechanical, egress, and insulation — and issues a Certificate of Occupancy when everything passes. The C of O is required before the ADU can be legally occupied or rented.
Section 3 of 4
Construction & systems
What a complete garage-to-ADU conversion involves from demo to move-in.
What does a garage-to-ADU conversion include?
Structural upgrades to meet habitable space requirements, insulation to Washington energy code, framing of the garage door opening (new wall, windows, or separate entrance), rough plumbing (bathroom, kitchenette), rough electrical, HVAC installation, drywall, bathroom and kitchen finishes, flooring, paint, and trim — all permitted and inspected.
Does the ADU need a separate entrance?
A separate exterior entrance is strongly recommended for a rental ADU — both for privacy and for meeting the technical definition of a separate dwelling unit. We design and frame the entrance as part of the conversion.
What kitchen facilities are required in a Tacoma ADU?
A permanent cooking facility — at minimum a sink, a counter, and a means of cooking (range, cooktop, or built-in microwave/convection oven). A full kitchen with a range and dishwasher is typical for a long-term rental ADU. We scope the kitchen to the level that serves your rental market.
Section 4 of 4
Financial returns
What a Tacoma garage ADU costs to build and what you can expect in rental income.
What does a complete Tacoma garage-to-ADU conversion cost?
A complete garage-to-ADU conversion in Tacoma typically runs $80,000–$160,000 depending on the garage size, structural requirements, finish level, and whether a full kitchen or kitchenette is included. Your written proposal will itemize every cost before you commit.
How long until a Tacoma garage ADU pays for itself?
At $1,400–$1,800/month rental income (a realistic range for a well-finished Tacoma ADU), a $100,000 conversion breaks even in 5–7 years — and appreciates the home's value in the meantime. We discuss realistic payback scenarios during the consultation.
Are there any Tacoma or Washington programs that help fund ADU construction?
Washington State has periodically offered ADU incentive programs through the Housing Finance Commission. Tacoma also has programs aimed at increasing rental housing supply. We stay current on available programs and will flag any that apply to your project during the consultation.
Ready to talk about your project?
Free on-site consultation, written proposal at the end. Call 1-888-484-3132 or book online.