Typical Lot Size
10,000 – 43,560+
sq ft
Max ADUs
2
per lot
Permit Type
Type I (administrative)
Timeline
4 – 6 weeks
Median Home Price
$450,000 – $550,000
Est. ADU Rent
$1,400 – $1,800/mo
Neighborhood Overview
Birchwood offers the largest residential lots in Bellingham, with deep parcels ideal for detached ADUs and multi-unit potential. Located north of downtown along the Squalicum Creek greenway, this neighborhood is a top candidate for ADU development.
Birchwood is defined by its deep, oversized lots, many of which back onto the Squalicum Creek greenway. Originally developed as a working-class neighborhood, it has retained a mix of modest single-family homes on generous parcels. The deep lot configuration makes rear-yard detached ADUs especially practical, and several properties have the acreage to support two ADUs or even subdivision. Proximity to WTA transit routes along Meridian and Northwest Avenue qualifies many parcels for parking exemptions.
Many Birchwood lots exceed a quarter acre, and some parcels are over one acre. Deep lot configurations (50 ft wide x 200+ ft deep) are common, providing ample rear-yard space for a DADU.
ADU Construction Allowed
Birchwood qualifies for ADU construction under Bellingham's updated ordinance (BMC 20.10.036) and Washington's HB 1337.
- Detached ADUs (DADUs) allowed
- Attached ADUs allowed (basement, addition, above-garage)
- Up to 2 ADUs per lot
- Parking exempt (near transit)
Transit routes: WTA Route 27 (Meridian), WTA Route 26 (Northwest)
Why Build an ADU in Birchwood
- Largest residential lots in Bellingham — many over 10,000 sq ft
- Deep lot configurations ideal for rear-yard detached ADUs
- Up to 2 ADUs per lot under HB 1337 and city ordinance
- Subdivision potential on lots exceeding 10,000 sq ft
- Transit parking exemptions along Meridian and Northwest corridors
Special Considerations
Squalicum Creek buffer
Properties near the creek require a critical areas assessment. Buffer zones (typically 50–100 ft from the ordinary high water mark) reduce buildable area and may shift your ADU footprint.
Historic mining activity
Portions of Birchwood were mined in the early 1900s. Some parcels may require geotechnical soil testing before foundation work, adding $2,000–$5,000 to project costs.
Extended utility runs
On deep lots (200+ ft), sewer and water connections to a rear-yard DADU can add $5,000–$15,000 depending on distance from the main line.
City monitoring of multi-unit development
As one of the first neighborhoods seeing multi-ADU projects, Birchwood parcels may receive closer scrutiny during the permit review process.
Learn more about ADU regulations: Review Bellingham ADU laws, understand the permitting process, or see the complete cost breakdown for Whatcom County.
Ready to get started? Our free feasibility study analyzes your specific parcel in 48 hours.
Frequently Asked Questions
Can I build an ADU on my Birchwood lot?
Most Birchwood lots qualify for at least one ADU, and many qualify for two. The primary factors are zoning designation, lot size, setback compliance, and proximity to Squalicum Creek. Our free feasibility study checks all of these automatically using GIS data for your specific parcel.
How big are Birchwood lots compared to other Bellingham neighborhoods?
Birchwood has some of the largest residential lots in Bellingham, typically ranging from 10,000 to over 43,560 sq ft (one acre). For comparison, Sunnyland lots average 4,000–7,000 sq ft. This extra space makes Birchwood ideal for detached ADUs, and some lots are large enough for subdivision or two ADUs.
What are the Squalicum Creek restrictions for ADUs in Birchwood?
Properties within approximately 200 feet of Squalicum Creek may require a critical areas assessment. Buffer zones — typically 50 to 100 feet from the ordinary high water mark — restrict construction. Your ADU can still be built outside the buffer, but the setback reduces available building area. Our feasibility study maps the exact buffer on your parcel.
Can I build two ADUs on my Birchwood property?
Under Washington's HB 1337 and Bellingham's updated ordinance, residential lots can have up to two ADUs in any configuration: two detached, two attached, or one of each. In Birchwood, the large lot sizes make dual-ADU projects especially practical. The combined rental income from two ADUs can reach $2,800–$3,600 per month.
