Lot Coverage Limits: Gresham vs Portland
How do lot coverage limits rules compare between Gresham, OR and Portland, OR?
Gresham has fewer restrictions than Portland.
Gresham, OR
Multnomah County
Portland residential zones cap lot coverage at 50% in R5/R7 and 60% in R2.5 (PCC 33.110). Unincorporated Multnomah County RR zones typically cap at 25% building coverage. Lot coverage calculations include the footprint of all structures with a roof. Stormwater management requirements apply to impervious surfaces over 500 sq ft or 50% of the lot.
View full Gresham rules →Portland, OR
Multnomah County
Portland's Title 33 (Planning and Zoning) limits the maximum building coverage (lot coverage) in residential zones. The R5 zone allows up to 45% lot coverage for primary structures plus accessory structures. Coverage limits help maintain open space, stormwater infiltration, and neighborhood character.
View full Portland rules →Key Facts Comparison
| Fact | Gresham | Portland |
|---|---|---|
| Portland R5 | 50% max coverage | - |
| Portland R2.5 | 60% max coverage | - |
| Stormwater Trigger | 500 sq ft impervious | - |
| Rural County | 25% max typical | - |
| Code | PCC 33.110.225 | - |
| Governing Code | - | Title 33 (Planning and Zoning) |
| R5 Zone Coverage | - | 45% maximum building coverage |
| Includes | - | All structures — primary + accessory |
| ADUs | - | Count toward lot coverage |
| Stormwater | - | Impervious surface triggers SWMM |
Highlighted rows indicate differences between cities.
Gresham FAQ
Does my deck count toward lot coverage?
Only if it has a roof. Uncovered decks count as impervious surface for stormwater purposes but not building coverage in Portland.
Can I use permeable pavers to exceed coverage limits?
Permeable pavers count as impervious under Portland code but may reduce stormwater fees under Clean River Rewards. Building coverage (roofed) limits still apply.
Portland FAQ
How much of my lot can I build on in Portland?
In the R5 zone, maximum building coverage is 45% of the lot area. This includes all structures — the primary dwelling, garage, ADU, shed, and other accessory structures. Other zones have different limits.
Do driveways count toward lot coverage?
Driveways, patios, and walkways count as impervious surface but not building coverage. However, exceeding impervious surface thresholds triggers stormwater management requirements under Portland's SWMM.
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