Do I need a permit for an accessory dwelling unit (ADU) in
Bremerton, Washington?

Bremerton ADU permits — the key details

Washington state law RCW 36.70A.680 (effective 2021, expanded 2023) requires all cities to allow at least one ADU per single-family lot without owner-occupancy, design, lot-size, or parking requirements. Bremerton has codified this into its municipal code and applies it city-wide. The City of Bremerton Building Department will not reject an ADU application based on lot size, setback (beyond standard 10–20 ft side yard), or the requirement that you live on-site; this is a state-mandated override of old zoning rules. However, Bremerton still requires a full building permit, architectural plans, and IRC compliance (foundation, egress, utilities, sprinklers if total dwelling units exceed three on the lot). The permit application must include a site plan, floor plan, elevations, foundation details (if detached), and utility connections (separate or sub-metered). Single-story garage conversions and junior ADUs (created inside the primary home by adding a kitchenette and separate entrance) are treated the same as detached new builds: all require permits and plan review.

Egress is the most common rejection reason in Bremerton ADU applications. Every habitable room, including bedrooms, must have a second exit (IRC R310.1). For a garage conversion, this usually means a second door or operable window sized 5.7 sq. ft. minimum with a sill height no more than 44 inches. For a detached ADU, a single entrance is acceptable if the sleeping room has a compliant window; for a two-bedroom ADU, you typically need a main entrance plus a bedroom egress window. The city inspects egress strictly because Kitsap County has high wildfire risk zones nearby, and evacuation routes are scrutinized. Separate utility connections (water, sewer, electric) or a sub-metered arrangement must be shown on plans and approved by Bremerton Public Utilities. If the ADU draws utilities from the primary home's meter, the utilities department may demand a sub-meter ($500–$1,500 installation), and the building department will flag this during plan review.

Parking is often waived in Bremerton. State law removed parking requirements for ADUs, and the city has not re-imposed them; however, if your lot is on a narrow street or near a transit center (the Bremerton Transit Center is downtown), the planning division may note in writing that off-site parking is acceptable. Street parking counts as available parking. If you propose a detached ADU on a 4,000 sq. ft. lot in a flood zone or on a slope steeper than 20%, the city may require a geotechnical report ($2,000–$4,000) before issuing a foundation permit. Frost depth in Bremerton proper is 12 inches due to maritime influence, but eastern neighborhoods near Highway 3 can see 18–24 inches; the building department will specify footing depth on the permit. Detached ADUs must be on a proper foundation (crawlspace, slab-on-grade, or post-and-pier); no mobile ADUs are permitted.

Sprinkler requirements hinge on total square footage of all dwellings on the lot. If the ADU plus primary home exceeds 5,000 sq. ft., fire sprinklers are required in the ADU (IRC R313.2). Most single-story detached ADUs (400–800 sq. ft.) do not trigger sprinklers because the primary home is usually under 4,000 sq. ft. A junior ADU (in-home conversion, typically 200–400 sq. ft.) almost never triggers sprinklers. Confirm square footage with the city during pre-application. Bremerton also enforces energy code (Washington State Energy Code, one cycle behind current, typically 2021 standard) and electrical code (NEC); all wiring must be inspected, and sub-panel or separate service must be signed off by city inspector. Plan review takes 2–3 weeks for straightforward applications; addendums and resubmittals add another 2–4 weeks.

Timeline from application to final inspection is typically 8–12 weeks for a garage conversion or junior ADU, and 12–16 weeks for a new detached build. The sequence is: application intake (1 week), plan review (2–3 weeks), pre-construction meeting, foundation inspection (1 day on-site), framing inspection (1–2 days), rough trades (mechanical, electrical, plumbing), insulation, drywall, and final inspection. You do not need a separate planning permit for ADU (state law prohibits conditional use permits), but you do need a building permit, mechanical permit (if new HVAC), electrical permit (if new service), and plumbing permit (if separate connections). Combined permit fees in Bremerton total $4,000–$12,000, depending on square footage and complexity. A 600 sq. ft. garage conversion typically runs $4,500–$7,000 in permit fees; a 800 sq. ft. detached ADU with new utility connections and engineering, $8,000–$12,000. Owner-builders are allowed if the ADU will be owner-occupied; you can pull permits in your own name, but you must attend the pre-construction and final walk-throughs.

Three Bremerton accessory dwelling unit (adu) scenarios

Washington state ADU law and how it overrides Bremerton zoning

In 2021, Washington state passed RCW 36.70A.680, requiring all cities to allow at least one ADU per single-family residential lot without owner-occupancy, design review, lot-size, or parking restrictions. Bremerton adopted this by ordinance in 2022 and cannot reject ADU applications based on local zoning restrictions that contradict state law. This is fundamentally different from the surrounding unincorporated Kitsap County, which still requires owner-occupancy and applies conditional use permit requirements to ADUs on lots under 10,000 sq. ft. Within Bremerton city limits, you can build an ADU on a 5,000 sq. ft. corner lot in a single-family zone without the primary homeowner living on-site, which would have been flatly prohibited before 2021.

However, Bremerton still enforces the International Building Code (IRC), Washington State Energy Code, and the National Electrical Code. The fact that state law forbids 'owner-occupancy' restrictions does not mean the city waives building quality standards; you still need a full permit, plan review, and inspections. The city's job is to ensure structural safety, egress, utilities, and compliance with energy and electrical codes—not to enforce occupancy restrictions. This distinction confuses many applicants who think 'ADU law means no permit.' The state law prohibits the city from imposing zoning restrictions; it does not prohibit the city from enforcing safety codes. If your ADU has illegal egress, non-compliant electrical, or inadequate foundation, the permit will be denied or conditioned.

The second ADU question: can you build two ADUs on one lot? Washington state law (RCW 36.70A.680) requires at least one, but does not prohibit more. Bremerton's municipal code currently allows one ADU per single-family lot (as of 2023). A second ADU would require a zoning variance or code amendment, which is unlikely to be granted. If you are considering a duplex or two separate detached buildings, you will need a land-use compatibility statement or rezone, not just a building permit. Check with the planning division before committing to a two-unit design.

One more state-law nuance: ADUs created under RCW 36.70A.680 are explicitly allowed to be rented out without restriction. There is no requirement that you occupy the primary home while renting the ADU. This contrasts with some older local ordinances that required owner-occupancy. Bremerton's current code does not impose owner-occupancy as a condition of the ADU permit; however, some lenders and HOAs may still impose restrictions on rentals. Check your mortgage note and HOA covenants before assuming you can rent out the ADU freely. The city permit will not prevent you from renting, but private deed restrictions might.

Bremerton's permit review process: online portal limitations and why in-person filing may speed approval

Bremerton's building permit portal (managed through the city website) allows online applications for simple projects like minor electrical or plumbing work, but ADU applications with architectural drawings, site plans, and structural details are often faster to submit in person or by mail with hard copies. The online system has a 5 MB file limit per document and does not easily accommodate multi-sheet construction sets. Most applicants end up printing a full set (typically 6–12 sheets for a garage conversion, 15–20 sheets for a detached ADU), submitting in person at City Hall (614 5th Street, Bremerton, WA), and scheduling a pre-application meeting with the building official to clarify expectations before formal review begins. This pre-application meeting (optional but recommended) costs $150–$250 and takes 30 minutes; it often saves 1–2 weeks of back-and-forth by clarifying code issues upfront.

Plan review in Bremerton is performed by the building department (not contracted to an outside firm). Reviews take 10–15 business days for a straightforward application; complex projects (detached ADU with utility work, geotechnical concerns, or hillside placement) may take 3–4 weeks. The city issues a single addendum letter listing all deficiencies; you revise and resubmit. Most ADU applications get one addendum, occasionally two. Resubmittal review takes another 5–10 days. Once approved, the city issues a building permit and you can request inspections. The permit is valid for 18 months; if work is not started by then, it expires and you must re-apply (and re-pay).

Utility connections (water, sewer, electric) are handled by separate departments: Bremerton Public Utilities (water/sewer) and Puget Sound Energy (electric). You must have approved utility plans as part of your building permit application, but you obtain separate utility permits and schedule tap connections once the building permit is issued. Utilities approval can take 2–4 weeks; if you need new sewer or water mains extended, timeline extends to 8–12 weeks and costs jump to $5,000–$15,000. Most lots in Bremerton proper have existing water and sewer lines; verify this early by calling Bremerton Public Utilities at (360) 475-3500 (confirm current number) and requesting a site plan review.

Weather impacts timeline modestly in Bremerton. The city does not shut down for rain (typical for the Pacific Northwest), but winter frost and dark days (November–March) can slow site inspections and framing work. If you apply for a permit in October, plan review happens in November, and you will be ready for pre-construction and foundation work in December–January; expect occasional delays due to weather-related inspector availability. Spring (April–June) is the fastest permitting season because inspection queues are shorter and daylight is longer. If you have a January start date in mind, file your application by October.

Common questions