Hillsboro, OR Building Setbacks & Zoning: Lot Coverage Limits (2026)
Key Facts
- R-10 interior lot cap
- 40% of lot area
- R-10 corner lot cap
- 45% of lot area
- What counts
- buildings over 24 inches tall
- Cottage clusters
- exempt from this standard
- Governing section
- CDC § 12.21.150, Table 12.21.150-1
Summary
In Hillsboro's R-10 single-family zone, buildings can cover no more than 40% of an interior lot or 45% of a corner lot; other zones set their own caps.
Maximum Lot Coverage 40% for interior lot 45% for corner lot Does not apply to cottage cluster lots. Lot coverage for townhouses is calculated based on the overall townhouse project, rather than each townhouse lot. Minimum Usable Open Space Variable See Section 12.50.210 Minimum Landscaping Not applicable
* Standards illustrated in Figure 12.21.150-A
Figure 12.21.150-A: Development Standards in the R-10 Zone Figure 12.21.150-A: Development Standards in the R-10 Zone
(Ord. 6401 § 1, 2022; Ord. 6323 § 1, 2019; Ord. 6120 § 1, 2015)
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Municipal Code: Supplement 1 | Community Development Code: Supplement 1).
Full Breakdown
Hillsboro's Community Development Code caps building footprint as a share of lot area. In the R-10 zone (the city's standard single-family district, 10,000-sq.-ft. minimum lots), Table 12.21.150-1 sets maximum lot coverage at 40% for an interior lot and 45% for a corner lot. Lot coverage is defined in CDC § 12.01.500 as the lot area covered by buildings taller than 24 inches above native grade, expressed as a percentage of lot area, so low decks and paving aren't counted. The cap doesn't apply to cottage cluster lots, and townhouse coverage is figured across the overall project rather than per lot. Other residential and commercial zones carry different coverage maximums under their own development-standards tables.
Violations & Fines
Building beyond the coverage cap requires an approved Variance or Adjustment under CDC §§ 12.80.150-12.80.156 before construction; the Planning Division can reject a building permit or issue a stop-work order for coverage that exceeds the approved plan.
Frequently Asked Questions
Does Hillsboro's lot coverage limit count patios and low decks?
Is 40% the lot coverage limit everywhere in Hillsboro?
Sources & Official References
Other rules in Hillsboro
Compare Hillsboro to another location·View the Oregon building setbacks & zoning overview
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