Whatcom County, WA Zoning Overlays & Bonuses: Density Bonus Law (2026)
Key Facts
- Base bonus cap
- 35% over underlying zone density
- Birch Bay bonus
- Up to 100%, Resort Commercial, outside floodplain
- Bonus stacking
- Additive credits, not compounded
- Ineligible area
- Water Resource Protection Overlay District
- Governing chapter
- WCC Chapter 20.85, Planned Unit Development
- Verification point
- Final PUD review under WCC 20.85.365
Summary
Whatcom County lets Planned Unit Developments earn up to a 35 percent density bonus above the underlying zone under WCC 20.85.108, stacking additive credits for open-space improvements, historic preservation, energy efficiency, renewable heat and shoreline public access. In the Birch Bay Urban Growth Area's Resort Commercial zone, single-family PUDs can instead double base density, up to 100 percent, outside the floodplain.
§ 20.85.108. Density increases. (1) The county may approve an increase of dwelling unit density for residential development, or floor area for commercial and industrial activities of not more than 35 percent greater than that permitted by the underlying zone. Properties located within a Water Resource Protection Overlay District shall not be eligible for a dwelling unit density increase. ... are to be treated as additive, and not compounded: (a) A 15 percent increase in base density for meeting the requirements of this chapter. ... (f) A 15 percent increase in the base density for the creation and preservation of significant public access on shorelines. ... (4) In a Resort Commercial zoning district located within the Birch Bay UGA, the County may approve an increase of dwelling unit density for single-family dwellings of not more than 100 percent greater than that permitted by the underlying zone, if the following criteria are met: (a) The dwellings are located outside the floodplain; and (b) No density increases for residential development are granted pursuant to subsection (1) of this section; and (c) Density credits are acquired pursuant to Chapter 20.91 WCC.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4963078; v4 updated 2026-06-23; through 06-23-2026).
Full Breakdown
85, is the only path to added residential density beyond a project's base zoning; a standalone lot outside a PUD cannot claim a density bonus. 108(1), the zoning administrator may approve a residential density increase, or added floor area for commercial and industrial PUDs, of up to 35 percent above what the underlying zone allows, rounded to the nearest whole number. Properties inside a Water Resource Protection Overlay District, which shields the Lake Whatcom drinking-water watershed, are categorically ineligible for any bonus. The remaining credits are additive, not compounded, and include: 15 percent for meeting the chapter's baseline PUD standards; 10 percent for built recreational open space such as trails, courts or pools; 10 percent for preserving a historically or architecturally significant structure, subject to the planning director's sign-off no later than technical committee review; 10 percent for buildings that cut energy use to 75 percent or less of the Washington State Energy Code baseline; 10 percent for on-site renewable energy covering at least 20 percent of combined space and water heating; 15 percent for preserving public shoreline access; and a separate 15 percent rear-lane/alley-garage design bonus for single-family and multifamily projects in urban residential zones. 91 WCC's transfer-of-development-rights program. 365.
Violations & Fines
A PUD that builds beyond its approved density, or claims a bonus percentage it never actually qualified for, is a zoning code violation Whatcom County Planning and Development Services pursues through its standard land-use enforcement process. Bonus eligibility documentation, especially the energy-performance analysis required for the two energy-related credits, must be submitted and verified at final project review under WCC 20.85.365 before the project can proceed; unsupported bonus claims are stripped at that review, and any density built without an approved bonus can force a permit correction or stop-work action.
Frequently Asked Questions
How much extra density can a Whatcom County PUD earn?
Does the density bonus apply to any parcel, or only PUDs?
What is the Birch Bay density bonus?
Can a project stack every bonus category at once?
Sources & Official References
Other rules in Whatcom County
Compare Whatcom County to another location·View the Washington zoning overlays & bonuses overview
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