ADU & DADU Construction in Puyallup, WA

Washington Changed the Rules for Homeowners

In 2023, Washington passed House Bill 1337, and it took effect on July 1, 2025. It’s one of the biggest changes to residential construction in the state in decades. The law requires every city in Washington to allow at least 2 accessory dwelling units (ADUs) on any residential lot. The law also eliminated owner-occupancy requirements, capped impact fees at 50% of what the primary dwelling pays, set a minimum allowable ADU size of 1,000 square feet (cities cannot restrict below this), set a minimum height allowance of 24 feet, and allows ADUs to be sold independently as condominium units. Puyallup adopted its compliance rules through Ordinance 3324 in June 2025, and homeowners are starting to realize what this means: you can now add a fully legal, rentable living space to your property.

I’ve been watching this market closely. ADU construction combines everything I already do. Framing, plumbing, electrical, kitchen buildouts, bathroom construction, flooring, countertops, drywall, and finish carpentry. It’s a full remodel in a compact package. The difference is that instead of updating an existing room, you’re creating an entirely new living space.

What Is an ADU?

An accessory dwelling unit is a secondary living space on the same lot as your primary home. It has its own kitchen, bathroom, and sleeping area. There are two types:

Attached ADU - Built within or attached to the existing home. Garage conversions, basement apartments, and additions that connect to the main house. These are typically less expensive because you’re working with an existing structure.

Detached ADU (DADU) - A separate building on the same lot. Backyard cottages, converted detached garages, and above-garage apartments. These cost more but offer complete privacy and separation from the main home.

Why Puyallup Homeowners Are Building ADUs

I’ve talked to dozens of homeowners about ADUs in the past year, and the reasons fall into three buckets.

Rental income. A 500 square foot ADU in Puyallup rents for $1,200-$1,800 per month depending on finishes and location. That’s $14,400-$21,600 per year in income from space you weren’t using. Most ADUs pay for themselves in 5-8 years through rental income alone. After that, it’s pure income on top of the property value increase.

Family housing. Aging parents who need to be close but want their own space. Adult children saving for their first home. Visiting family who need more than a guest room. An ADU gives your family member a real home with their own kitchen, bathroom, and entrance, 30 feet from your back door. I’ve built ADUs for families in exactly this situation, and every single one has said it changed their family dynamic for the better.

Property value. A well-built ADU adds $100,000-$200,000 to your property value in the Pierce County market. It’s one of the highest-return home improvement investments you can make, and the new state law makes it legal on virtually every residential lot. Under HB 1337, you can also sell your ADU as a separate condominium unit, independent of the main home. Cities cannot prohibit this. That gives you a future exit strategy that didn’t exist before.

Garage Conversions: The Most Cost-Effective Option

If you have an attached or detached garage you don’t fully use, a garage conversion is the fastest and most affordable path to an ADU. The structure is already there. The foundation, walls, and roof exist. One important detail from HB 1337: existing structures can be converted to ADUs even if they currently violate setback or lot coverage requirements. That means your old detached garage sitting 3 feet from the property line is still a candidate. Here’s what we add:

Insulation and climate control. Most garages have no insulation. We insulate walls, ceiling, and the garage door wall (which gets framed in with a window or sliding door). An efficient mini-split system handles heating and cooling year-round.

Plumbing. A full bathroom (toilet, vanity, shower) and a kitchen with sink and dishwasher hookup. We tie into the existing water supply and waste lines from the main house. In most cases, the utility connections are within 15-20 feet.

Electrical. A dedicated sub-panel for the ADU with its own circuits for kitchen appliances, HVAC, lighting, and outlets. We wire to current code with GFCIs in wet areas and AFCIs in living spaces.

Finished interior. Drywall, flooring, kitchen cabinets and countertops, bathroom tile, lighting fixtures, and trim work. I build ADU kitchens and bathrooms to the same quality standard as my full remodeling projects. No corners cut.

Separate entrance. Every ADU needs its own entrance. For garage conversions, we typically install a new exterior door where the garage door opening was, or on a side wall.

Typical garage conversion cost: $78,000-$190,000 depending on size and finishes. Timeline: 8-14 weeks from permit to move-in.

Backyard Cottages (DADU): Built From the Ground Up

For homeowners who want maximum separation between the main home and the ADU, or who don’t have a garage to convert, a detached accessory dwelling unit is the answer. These are standalone structures built on your lot with their own foundation, walls, roof, and utility connections.

I work with local architects to design DADUs that complement your existing home and maximize the available space on your lot. Common sizes range from 400 to 800 square feet. A 600 square foot DADU typically includes a one-bedroom layout with an open kitchen and living area, a full bathroom, a closet, and a small laundry area.

Typical DADU cost: $155,000-$400,000+ depending on size, foundation type, and finishes. Timeline: 12-20 weeks from permit to move-in.

Important: Puyallup’s Lahar Zone Restriction

If your property is in Puyallup, there’s one critical thing to check first. The City of Puyallup prohibits ADU construction on lots within the designated volcanic hazard (lahar) zone, except for properties within one-half mile from the base of the surrounding elevation of the Puyallup valley floor. This restriction is unique to Puyallup because of its proximity to Mount Rainier lahar pathways. The city has an Interim Middle Housing Applicability Mapbook that shows which properties are eligible. I check this during the initial consultation so you know right away whether an ADU is an option on your lot. If your property is in the restricted area, you can still add interior additions or guest rooms, but a separate ADU that can be rented full-time is not permitted. Contact the City of Puyallup Planning Division at (253) 864-4165 or email Planning@PuyallupWA.gov with questions about your specific property.

The Puyallup ADU Permit Process

The permitting process is the part most homeowners dread, and it’s the part I handle completely. Here’s what’s involved:

1. Site plan review. The City of Puyallup reviews your lot to confirm ADU eligibility, setback compliance, lot coverage, and utility access. Most standard residential lots qualify.

2. Building permit application. I submit the full construction drawings, structural calculations (when required), and the building permit application. For DADUs, this includes architectural plans, engineering, and sometimes a site survey.

3. Utility coordination. Water, sewer, and electrical connections need to be approved. For attached ADUs tying into existing utilities, this is straightforward. For detached units, it may require new utility runs and separate meters.

4. Inspections. Foundation, framing, plumbing rough-in, electrical rough-in, insulation, and final inspection. I schedule each one and am on-site for every inspection.

5. Certificate of occupancy. Once the final inspection passes, the city issues a certificate of occupancy and the unit is legal for habitation.

The permit process adds 4-8 weeks to the project timeline. I submit applications early and follow up with the city to keep things moving. I’ve been pulling permits in Puyallup since 2018 and know the process inside and out.

Is an ADU Right for Your Property?

Not every lot works equally well for every type of ADU. During the free consultation, I walk your property, review the lot dimensions, check utility locations, and discuss which ADU type makes the most sense for your goals and budget.

Some questions I’ll help you answer:

• Does your lot have enough space for a detached unit?
• Is your garage a good candidate for conversion?
• What are the setback requirements for your zone?
• How will utilities connect to the new unit?
• What rental income can you realistically expect in your neighborhood?
• What’s the most cost-effective approach for your specific property?

I give you a straight answer, not a sales pitch. If an ADU doesn’t make financial sense for your situation, I’ll tell you that too.

Ready to explore your options? Call me at (253) 392-9266 or request a free estimate. I’ll walk your property, discuss the possibilities, and give you a realistic number.