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Planning and Development Services offers pre-approved detached accessory dwelling unit (DADU) plans for use within the City of Tacoma jurisdiction. There are four base models with different roof types, siding styles, and ground floor dwellings meeting visitability design standards. These units were designed to fit adopted Home in Tacoma zoning standards as backyard detached accessory dwelling units. Layouts are compact with smaller footprints to encourage density and more affordable housing options.
ADVANTAGES OF USING A CITY OF TACOMA PRE-APPROVED DADU PLAN
- Streamlined Permitting – Plans are compliant with building, residential, and energy codes, so you can obtain permits and plan checks quickly.
- Extensive Pre-Application Process – City staff will provide site specific information to customers, so site plan preparation is easier. We conduct a site visit with you and your contractor to go over site specific conditions during the pre-application process to avoid common issues at time of development.
- Save Time and Money – With a pre-approved plan, you’re likely to cut costs and enjoy a more convenient construction process. The cost of preparing the plans, evaluating the site for services, and City support information is included and initially free.
- Customizable – Plans have several options, though if additional modifications are desired beyond the pre-approved plan sets, then applicants must work with the designer to modify. Modified plans will incur separate fees and expenses required to be paid to the designer by the customer. Substantial changes to the plans will require discussion with City staff to determine if the scope remains within this program.
ITEMS TO CONSIDER WHEN CHOOSING TO BUILD YOUR DADU
- The plans may not work for the site. If you opt to use a pre-approved plan, you still need to go through the required checks to ensure the plan can be built on your lot. This is typically evaluated in discussion with staff and during the site visit.
- Pre-approved plans are not right for all While the plans may be customized to fit specific needs, if those changes impact the structural aspects of the building, then it will likely not qualify under the City’s Pre-Approved Plan program. Minimal changes will allow you to maintain the pre- approved status, but larger changes to the floor plan are usually not permitted. Any changes would need to be reviewed and approved by building authorities, adding more cost and review time.
- Permits required. A pre-approved plan is not pre-permitted. Site-specific evaluations are required and review for items not pre-approved like utility service, critical areas, historic districts, proximity to fire hydrants and apparatus service, and other non-confirming and uncommon situations may result in additional permitting requirements. These items should be identified by the customer and discussed during the pre-application and site visit stages.
ZONING DISTRICT LOCATION
Depending on the property location and zoning designation, the DADU has specific requirements. Common items include setbacks from property lines, distances between structures, building coverage, design standards, landscape and tree canopy coverage, pedestrian access, historic districts, height limits, off-street parking, and other considerations. Environmentally sensitive areas like wetlands, streams, flood plains, steep slopes, biodiversity areas must be identified.
UTILITY SERVICES
Existing and proposed service connections must be identified. In most cases, services must not be through or directly connected to an existing structure. Water service from existing meter must be adequate to serve all dwellings. Contact Tacoma Water if new meter is proposed. Shared sanitary service is allowed if meeting the City’s Side Sewer Manual. Solid waste bin storage and pick-up locations must be clarified. Clearances from existing power lines and new services must be directed to Tacoma Power. Storm water and impervious surfaces must be per the City’s Stormwater Management Manual and must be detailed on plans with additional documents as necessary.
BUILDING / ENERGY / FIRE
Not all site-specific building situations have been addressed with the pre-approved plans. If a site has environmental criteria beyond the approved design, then the plans will require additional modification at additional expense to the customer. Things like topographic wind impacts, fire separation distance issues, proposed modifications to the structure design, alternative energy options to name a few, will require additional consideration. Fire apparatus and hydrant distances must meet proximity requirements based on code and may result in additional requirements. Special inspection requirements may be necessary in some high wind areas.
PERMITS & FEES
Permits for accessory dwelling unit are required to be submitted under a residential building new construction permit. The permit will include plumbing and mechanical. Site development work will also be reviewed under that combination permit. Contact Tacoma Power for electrical and new service requirements. Scope outside of the residential new construction with site development will require additional permits. This is common for construction near critical areas, fire code mitigation, historic areas, non-conforming land use circumstances, right-of-way work not covered, and/or other permit situations.
Other fees to anticipate during or upon completion of construction include water service fee for the additional dwelling, sanitary sewer rate changes,
Permit Resources
Accessory Dwelling Units in UR Districts: ADU Zoning Tip sheet Land Use Regulatory Code Link: Title 13
Residential Permit Submittal Checklist
