Tacoma has quietly become one of the best cities in Washington for building a detached accessory dwelling unit. With lower construction costs than Seattle, a growing population of experienced DADU contractors, and city regulations that actively encourage backyard cottage development, Tacoma homeowners are in a strong position to add living space and rental income to their properties.

If you're considering a DADU in Tacoma or the surrounding Pierce County area, here's what you need to know about the local builders, permit process, and costs.

Why Tacoma Is a Great Market for DADUs

Tacoma's municipal code has been progressively updated to support ADU and DADU construction. The city allows detached accessory dwelling units on most single-family residential lots, and recent state legislation — specifically HB 1337 — has made the regulatory landscape even more favorable. Key benefits of building in Tacoma include:

Top DADU Builders Serving Tacoma

1. Tacoma DADU

Tacoma DADU is the most specialized DADU builder in the Pierce County area. As their name suggests, backyard cottages are their entire focus, which means their team has deep expertise in Tacoma's specific zoning codes, permit requirements, and site challenges. They offer several pre-designed floor plans ranging from 400 to 800 square feet, as well as custom design services for homeowners who want something unique.

Their streamlined process — from initial site assessment through final inspection — typically takes 6 to 10 months. Tacoma DADU is particularly well-regarded for their transparent pricing and their ability to guide first-time ADU builders through the process without surprises.

2. Built Right Eco Workshop

Built Right Eco Workshop brings a sustainability-focused approach to DADU construction. They specialize in energy-efficient building techniques, including high-performance insulation, mini-split heat pump systems, and sustainable material sourcing. For homeowners who care about their environmental footprint — or who simply want lower utility bills in their rental unit — Built Right is a compelling choice.

Their projects tend to emphasize quality craftsmanship and thoughtful design, with attention to natural light, ventilation, and durable finishes that stand up to tenant use. They serve the broader South Sound area and have completed projects in Tacoma, Olympia, and surrounding communities.

3. United Signature

United Signature is a full-service construction company that handles ADUs alongside other residential projects. Their broader experience in home additions, renovations, and new construction gives them flexibility to handle complex projects — for example, combining a main house renovation with a new DADU in the backyard. They're a good fit for homeowners who want a single contractor to manage multiple improvements at once.

United Signature's team is familiar with permitting in both Tacoma and Seattle, so they can serve homeowners across the I-5 corridor. Their pricing is competitive, and they offer both design-build packages and construction-only services for homeowners who already have architectural plans.

4. New Image Construction & Management

New Image Construction & Management rounds out the Tacoma-area builder list with a solid track record in residential construction. They handle DADU projects from design through completion and are known for responsive communication and reliable timelines. New Image is a particularly good option for homeowners who value a hands-on project manager and clear weekly updates throughout the build process.

Tacoma DADU Permit Process

Building a DADU in Tacoma requires a building permit from the City of Tacoma's Planning and Development Services (PDS) department. Here's an overview of the process:

  1. Pre-application conference (optional but recommended): Meet with city planners to discuss your project, confirm zoning compliance, and identify any potential issues before you invest in full architectural plans.
  2. Submit building permit application: Include your site plan, architectural drawings, structural engineering, and energy code compliance documentation. Most builders handle this submission on your behalf.
  3. Plan review: The city reviews your plans for code compliance. This typically takes 3 to 6 weeks in Tacoma, faster than Seattle in most cases.
  4. Permit issuance and construction: Once approved, your builder can begin construction. Inspections are required at key milestones (foundation, framing, insulation, final).
  5. Final inspection and certificate of occupancy: After passing all inspections, the city issues a certificate of occupancy and your DADU is ready for use.

Tacoma's permit fees for a DADU typically run $5,000 to $9,000, depending on the project's valuation and scope. The city has been actively working to streamline ADU permitting in compliance with HB 1337, so the process is becoming more predictable each year.

Typical Costs and Timeline

For a standard 600 square foot DADU in Tacoma with mid-range finishes, expect the following:

These numbers are significantly lower than comparable projects in Seattle, making Tacoma one of the most cost-effective markets for DADU construction in the Puget Sound region. For a deeper dive into costs statewide, see our complete ADU cost guide.

Ready to connect with Tacoma-area DADU builders? Browse our Tacoma builder listings or request free quotes to compare pricing from multiple contractors.