The owner-occupancy requirement — the rule that the property owner must live on-site, in either the main house or the ADU — is no longer one rule. It is now two different rules, and the split runs along the jurisdiction line: the City of Bellingham repealed it; unincorporated rural Whatcom County kept it.
Investors, read this first: if you plan to rent both the main house and an ADU on a rural Whatcom County parcel outside a UGA, you may have no legal path. WCC 20.80.910 requires the owner to live on the property there, and allows only one ADU.
Owner-Occupancy at a Glance
City of Bellingham
Repealed
Up to 2 ADUs per lot
Owner-occupancy repealed effective December 23, 2025.
Source: BMC 20.10.036, as amended by Ord. 2025-12-035 (effective 2025-12-23)
Whatcom County — inside a UGA
Not required
Up to 2 ADUs per lot
Applies in UGAs excluding the LWWO, GC, AG, R and RF districts. The ADU is a permitted use.
Source: WCC 20.80.910
Whatcom County — rural, outside a UGA
Still required
1 ADU per lot
The owner must live on the property. Approval runs through an Administrative Approval Use (ADM) permit.
Source: WCC 20.80.910; ADM per WCC 22.05.028
City of Bellingham: Repealed
Before Ordinance 2025-12-035
- Owner had to live on-site, in either the primary home or the ADU
- Some properties carry a recorded owner-occupancy covenant from an earlier ADU approval
- Investors couldn't build ADUs and rent both units
After Ordinance 2025-12-035 (Effective December 23, 2025)
- No owner-occupancy requirement — the owner does not need to live on-site
- Up to 2 ADUs per lot, attached or detached
- Owner can rent the main home and the ADU(s) independently
- An ADU may be sold as a condominium unit
Source: BMC 20.10.036, as amended by Ordinance 2025-12-035 (passed 2025-12-08, effective 2025-12-23). Implements WA HB 1337 (2023), SB 5558 and SB 6015 (2025).
Already have a recorded covenant? If an earlier ADU approval recorded an owner-occupancy covenant against your title, the repeal does not remove it automatically. The owner must file a release. Do this before you sell, refinance, or rent both units.
Unincorporated Whatcom County: It Depends on the UGA Line
Outside city limits, Whatcom County rules apply — not Bellingham's — and the county treats parcels inside an Urban Growth Area (UGA) very differently from rural parcels.
Rural (Outside a UGA): Still Required
- Owner-occupancy required
- Limited to 1 ADU per lot
- Administrative Approval Use (ADM), a Type II process — the county publishes processing times of up to 100 days; approval is valid 2 years
- A detached ADU also needs a minimum parcel size (4.5 acres in rural districts; more in RR-I, Rural Forestry, Agricultural and the Lake Whatcom Watershed Overlay)
Bottom line: renting both the house and the ADU to tenants is not a use this rule provides for.
Inside a UGA: Not Required
- No owner-occupancy requirement
- Up to 2 ADUs per lot
- Permitted use — apply directly for a building permit, no separate land-use permit
Exclusions: this does not apply in the LWWO, GC, AG, R and RF districts, even inside a UGA.
Source: WCC 20.80.910 (ADU standards); WCC 22.05.028 (ADM, Type II). Fees under the 2025–2026 Unified Fee Schedule, Ordinance 2024-063 (in force through 2026-12-31). Rules as of 2026-10-05.
What This Means For You
Homeowners Living On-Site
Living on-site works in every jurisdiction. In the City of Bellingham and in county UGAs you're no longer required to stay; on a rural county parcel outside a UGA, your residency is what makes the ADU allowed.
Real Estate Investors
In the City of Bellingham and in Whatcom County UGAs, you can buy a property, build up to two ADUs, and rent every unit without living on-site. On a rural county parcel outside a UGA, you cannot: WCC 20.80.910 requires owner-occupancy and allows only one ADU.
Homeowners Planning to Move
In the City of Bellingham and county UGAs, you can move out and keep renting both units. On a rural county parcel outside a UGA, owner-occupancy is a condition of the ADU — confirm with Whatcom County Planning & Development Services before you plan a move around rental income from both units.
Ready to run the numbers? See our ADU cost breakdown for Whatcom County or pricing page to understand the full investment. Then book a free 30-minute consultation to talk through which jurisdiction your parcel is in and what's possible on it.
Important Caveats
A previously recorded owner-occupancy covenant on a City of Bellingham property does not disappear on its own — the owner must file a release.
Check whether your parcel is inside a UGA before you plan anything. A Whatcom County address alone does not tell you which rule applies.
HOA CC&Rs may still require owner occupancy in some communities — covenant review is recommended.
Short-term rental restrictions are separate from owner-occupancy rules. Cities and the county can still regulate Airbnb/VRBO.
Mortgage requirements may have their own occupancy stipulations independent of local law.
Insurance coverage may differ for non-owner-occupied rental properties.
Last verified: October 5, 2026. Not legal advice. Verify current regulations with City of Bellingham Planning or Whatcom County Planning & Development Services.
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