Boulder vs Portland: ADU, STR & Home Business Rules Compared (2026)
Compare ADU owner-occupancy and parking preemption, short-term rental permits, and home business rules between Boulder, CO and Portland, OR. Both states preempt local ADU restrictions, but the scope of each preemption differs.
Side-by-Side Comparison
Boulder vs Portland
| BoulderCO | PortlandOR | |
|---|---|---|
| ADUs Allowed? | Yes — required by right under Colorado HB24-1152 (CRS §29-35-403) | Yes — required statewide for cities over 2,500 population under Oregon ORS 197A.425(1)(a) |
| Owner Occupancy Required? | No ongoing requirement — Colorado HB24-1152 prohibits requiring an ADU to be owner-occupied, though the city may require a one-time residency check at application (CRS §29-35-403(2)(b)) | No requirement at all — Oregon's ADU statute defines 'reasonable local regulations' to exclude owner-occupancy requirements outright, with no residency-check exception (ORS 197A.425(1)(b)(B)) |
| Parking Required? | No — Colorado HB24-1152 prohibits requiring a new off-street parking space for an ADU, with limited exceptions (CRS §29-35-403(2)(a)) | No — Oregon's ADU statute bars cities from requiring additional off-street parking for an ADU (ORS 197A.425(1)(b)(B)) |
| STR Allowed? | Yes — requires a city-issued short-term rental license (Boulder Municipal Code §10-3-19) | Yes — permitted in all zones subject to Title 33 Chapter 33.207 (Portland City Code §33.207.030) |
| Registration Required? | Yes — a short-term rental license is required (Boulder Municipal Code §10-3-19) | Yes — a Type A accessory short-term rental permit is required (Portland City Code §33.207.040.A.2) |
| Registration Type | Short-Term Rental License (Boulder Municipal Code §10-3-19) | Type A accessory short-term rental permit (Portland City Code §33.207.040.A.2) |
| Home Business Allowed? | Yes — allowed by right if it meets accessory-use standards (Boulder Municipal Code §9-6-3(o)) | Yes — allowed by right unless specifically excluded (Portland City Code §33.203.030.A) |
| City Permit Required? | No — home occupations meeting the standards are allowed by right with no separate permit (Boulder Municipal Code §9-6-3(o)) | Yes — a Type B home occupation permit must be obtained from Portland Permitting & Development before starting (Portland City Code §33.203.060.A) |
Key Differences
Boulder and Portland both operate under state-level ADU preemption, but the two states drew the line differently. Colorado's HB24-1152 requires by-right ADUs and prohibits an ongoing owner-occupancy requirement, while still allowing a one-time residency check at the application stage (CRS §29-35-403(2)(b)). Oregon's ADU statute goes further on this specific point — it defines 'reasonable local regulations relating to siting and design' to exclude owner-occupancy requirements altogether, with no carve-out for even a one-time check (ORS 197A.425(1)(b)(B)). On parking, both states reach the same result (no additional off-street parking may be required) through their respective statutes, so this is a case of two different laws landing on the same outcome rather than one state being uniquely permissive. Short-term rentals and home businesses are both permitted in each city, but Portland requires a separate Type B home occupation permit for occupations that exceed the by-right threshold (Portland City Code §33.203.060.A), while Boulder's home occupation standards are satisfied by right with no additional permit step (Boulder Municipal Code §9-6-3(o)).
Cost Comparison
Boulder's ADU building permit fees run roughly $1,500–$5,000, and Boulder Valley School District impact fees of about $3,000–$6,000 may apply; Colorado HB24-1152 explicitly permits municipalities to continue charging impact fees for ADUs (CRS §29-35-403(3)(f)). Portland's ADU building permit fees run roughly $1,200–$3,500, with system development charges (transportation and parks) typically adding $10,000–$20,000 — a significantly larger fee category than Boulder's. Both ranges are drawn from each city's cached fee schedule; confirm current figures with Boulder Planning and Development Services or Portland Bureau of Development Services before budgeting.
Our Verdict
Both cities offer strong state-backed ADU rights with no ongoing owner-occupancy requirement and no added parking mandate, so the ADU-building experience is broadly similar. The practical difference shows up in system development charges — Portland's transportation and parks SDCs can add $10,000–$20,000 to a project, well above Boulder's fee range, which may tip the cost-benefit calculation toward Boulder for budget-conscious builders. On home businesses, Boulder's by-right approach is simpler than Portland's Type A/Type B permit distinction. For lower total ADU cost and simpler home-business rules, Boulder edges out Portland; for STR flexibility, both cities are comparably permit-friendly.
Explore Each City
Frequently Asked Questions
Do Boulder and Portland both prohibit owner-occupancy requirements for ADUs?
Both prohibit an ongoing owner-occupancy requirement, but the scope differs. Colorado's HB24-1152 lets Boulder require a one-time residency check at application (CRS §29-35-403(2)(b)); Oregon's ORS 197A.425(1)(b)(B) excludes owner-occupancy requirements from Portland's 'reasonable local regulations' with no such exception.
Which city has higher ADU system development fees, Boulder or Portland?
Portland. Its transportation and parks system development charges typically add $10,000–$20,000 to an ADU project, notably higher than Boulder's fee range of roughly $1,500–$5,000 in building permit fees plus $3,000–$6,000 in possible school impact fees.
Do I need a permit for a home business in Portland?
It depends on the type. Home occupations are allowed by right in Portland unless specifically excluded (Portland City Code §33.203.030.A), but a Type B home occupation requires a permit from Portland Permitting & Development before starting (§33.203.060.A). Boulder's qualifying home occupations are allowed by right with no separate permit.
Can both Boulder and Portland require additional parking for an ADU?
No. Colorado's HB24-1152 (CRS §29-35-403(2)(a)) and Oregon's ADU statute (ORS 197A.425(1)(b)(B)) both bar cities from requiring additional off-street parking for an ADU, with limited statutory exceptions.
Source: PropertyZoned Editorial Research. Last verified July 3, 2026.