Erosion Control: Gresham vs Portland
How do erosion control rules compare between Gresham, OR and Portland, OR?
Gresham has fewer restrictions than Portland.
Gresham, OR
Multnomah County
Multnomah County erosion control follows DEQ 1200-C NPDES permits for construction sites over 1 acre and local erosion control programs under PCC 10 (Portland) and GRC 6.18 (Gresham). Portland requires Erosion & Sediment Control Plans for all permitted earthwork. Best management practices include silt fences, straw wattles, stabilized construction entrances, and covered stockpiles. Sediment discharge to waterways carries severe penalties.
View full Gresham rules →Portland, OR
Multnomah County
Portland City Code Title 10 establishes mandatory erosion and sediment control requirements for all ground-disturbing activities. The Bureau of Environmental Services (BES) administers the program, requiring Erosion and Sediment Control Plans for construction sites. Portland's program implements federal Clean Water Act and Oregon DEQ NPDES permit requirements.
View full Portland rules →Key Facts Comparison
| Fact | Gresham | Portland |
|---|---|---|
| State Permit | DEQ 1200-C (>1 acre) | - |
| Portland Code | PCC Title 10 | - |
| Wet Season | Oct 1 - Apr 30 | October 1 through May 31 |
| Stabilization | 7-14 days | - |
| BMPs | Silt fence, wattles, inlet | - |
| Governing Code | - | Portland City Code Title 10 |
| Administering Agency | - | Bureau of Environmental Services |
| Plan Trigger | - | 500+ sq ft ground disturbance |
| Controls Required | - | Before any grading begins |
Highlighted rows indicate differences between cities.
Gresham FAQ
Do I need an erosion control plan for a small home addition?
In Portland, yes - all permitted earthwork requires at least a basic plan under PCC Title 10. Small sites often qualify for a simplified residential template.
What is a 1200-C permit?
DEQ's Construction Stormwater General NPDES permit, required for any land disturbance of 1 acre or more. It's issued under federal Clean Water Act authority.
Portland FAQ
Do I need an erosion control plan for a small project?
Any ground disturbance requires basic erosion controls. A formal Erosion and Sediment Control Plan is required for sites disturbing 500 square feet or more. Even smaller projects must prevent sediment from leaving the site.
Are there seasonal restrictions on construction?
Portland's wet season runs October 1 through May 31. Construction during this period triggers enhanced erosion control requirements. Additional BMPs and more frequent inspections may be required.
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