🏡 DADU & ADU Electrical
DADU & ADU Electrical Services — Seattle & Puget Sound
Fully permitted electrical installation for detached and attached accessory dwelling units throughout greater Seattle, Tacoma, Bellevue, Gig Harbor, Olympia, and Lacey. Separate service panels, sub-metering, and complete code-compliant wiring from start to final inspection.
Everything Your DADU Needs — Electrically
DADU electrical is more complex than most homeowners expect. We handle every piece — from utility coordination to the last outlet cover.
We coordinate with PSE and Seattle City Light to establish a new service connection or extend service from the main house to your DADU.
Your DADU gets its own 100–200 amp electrical panel, properly sized for the unit’s load and code-compliant for Seattle, King County, and Thurston requirements.
Renting your DADU independently? We install a sub-meter so utility costs are tracked and billed separately from your main home — required in Seattle for rental units.
All branch circuits, outlet boxes, switch boxes, and device rough-in wiring before drywall. Coordinated with your GC and all other trades.
We pull all required electrical permits through the City of Seattle, King County, Thurston County, or your local AHJ and see your project through final inspection sign-off.
Want your DADU EV-ready? We pre-wire or fully install a Level 2 EV charger circuit during construction — no wall-opening later.
Attached ADU vs. Detached DADU — Electrical Differences
Attached ADU
Shares the same structure as your main home — typically a basement conversion, garage conversion, or addition. May share the main service in some cases.
- May use subpanel off main house
- Separate meter if rented
- Simpler utility coordination
- Lower electrical cost typically
- AFCI/GFCI throughout required
Detached DADU
A separate backyard cottage or structure. Almost always requires its own electrical service entry, underground conduit run, and dedicated panel.
- Separate service & panel required
- Underground conduit to structure
- Separate meter for rental units
- Full NEC code compliance
- EV charger add-on available
Seattle’s DADU Building Boom — Why Electrical Matters
Seattle and cities across Puget Sound have dramatically loosened DADU (Detached Accessory Dwelling Unit) zoning rules in recent years. Today, most Seattle lots can accommodate a backyard cottage, and thousands of homeowners are building them — for rental income, multigenerational living, or long-term property value appreciation.
But DADU electrical is more complex than most homeowners expect. Unlike a simple addition to your main house, a DADU often requires a separate electrical service, a new meter base, utility coordination with PSE or Seattle City Light, and permits through both the city’s building department and electrical inspection division. Getting any of this wrong means failed inspections, costly rework, and project delays that affect your GC’s entire schedule.
Seattle & King County DADU Electrical Code Requirements
Seattle City Light and the City of Seattle have specific requirements for DADU electrical service. Key requirements include:
- Separate metering required if the DADU is rented independently (Seattle Municipal Code)
- Minimum 100-amp panel for most DADU sizes; 200-amp recommended for larger or EV-ready units
- AFCI protection on all applicable circuits per current WA NEC adoption
- GFCI protection in kitchen, bathroom, laundry, and outdoor areas
- Smoke and carbon monoxide detector interconnect wiring per WAC
- Outdoor weatherproof receptacles and lighting at all entrances
- Underground conduit sized and buried per local requirements
How Much Does DADU Electrical Cost in Seattle?
DADU electrical installation costs in Seattle typically range from $8,000 to $25,000+ depending on unit size, utility connection requirements, length of underground conduit run, and city permit fees. Larger, more complex projects with new utility service installation or sub-metering run toward the higher end. We provide detailed, line-item written estimates so you know exactly what to expect before any work starts.
We Work With Your DADU Builder
Already have a general contractor or DADU builder? We collaborate seamlessly with GCs across the Puget Sound area. We show up on schedule, communicate proactively about rough-in timelines, coordinate directly with PSE and the city AHJ, and manage the entire permit process so your GC can focus on keeping the build moving.
We’ve partnered with DADU builders throughout Seattle, Bellevue, Olympia, Tacoma, and the South Sound. If you need a referral to a DADU-focused GC, we’re happy to connect you with builders we know and trust.
When to Bring In an Electrician for Your DADU
The earlier, the better. Ideally, you bring us in during the design phase — before plans are submitted to the city. Early electrical planning helps identify utility service routes, underground conduit locations, panel placement, and whether any upgrades are needed at the main house. This avoids costly surprises mid-project and can actually save you money by reducing change orders.
DADU Electrical FAQ
Yes. Most DADUs in Seattle and across Puget Sound require a dedicated electrical panel separate from the main house. If the DADU will be rented independently, Seattle City Light requires separate metering as well. We handle all of this as part of our DADU electrical service — you don’t need to coordinate separately with the city or utility.
DADU electrical in Seattle typically ranges from $8,000 to $25,000+ depending on unit size, underground conduit run length, whether a separate utility service connection is needed, and permit jurisdiction. We provide free, detailed written estimates for every project.
In some cases, a subpanel fed from the main house can work for a small non-rented DADU. However, for most rented DADUs and any unit with significant electrical load, a separate service connection and panel is required. We’ll assess your situation and recommend the right approach during your free estimate.
Yes — we regularly partner with general contractors and DADU-focused builders throughout the Seattle and Puget Sound area. We communicate proactively, hit rough-in schedules, and handle all electrical permitting so your GC can focus on the build.
As early as possible — ideally during the design phase before plans are submitted. Early electrical planning identifies utility service routes, panel locations, and any main house upgrades needed before construction begins, avoiding costly mid-project surprises.
Absolutely. We can include a Level 2 EV charger circuit as part of your DADU electrical installation — either a full charger install or conduit pre-wire for a future charger. This is much easier and cheaper to do during construction than retrofitting later.