Flood Zones: Gresham vs Troutdale
How do flood zones rules compare between Gresham, OR and Troutdale, OR?
Gresham and Troutdale have similar restriction levels.
Gresham, OR
Multnomah County
Gresham participates in the NFIP and regulates development in FEMA-designated flood zones. Properties in the floodplain have strict building requirements including elevation certificates and flood-resistant construction.
View full Gresham rules →Troutdale, OR
Multnomah County
Troutdale participates in the FEMA National Flood Insurance Program and regulates development in Special Flood Hazard Areas (SFHAs) under Troutdale Development Code Chapter 14 (Flood Management), adopted by Ordinance 851 on January 17, 2019. SFHAs cover about 3% of the city — primarily along the Sandy River and Beaver Creek. Chapter 14 requires a 2-foot freeboard above base flood elevation for new and substantially improved residential structures, plus balanced cut-and-fill and engineer certification of no-rise.
View full Troutdale rules →Key Facts Comparison
| Fact | Gresham | Troutdale |
|---|---|---|
| NFIP | Participating community | - |
| Elevation | Must build above BFE | - |
| Certificate | Elevation certificate required | - |
| Key Area | Johnson Creek floodplain | - |
| Local Rule | - | Development Code Chapter 14 |
| Adopting Ordinance | - | Ord. 851 (Jan 17, 2019) |
| SFHA Coverage | - | About 3% of city; Sandy River & Beaver Creek |
| Freeboard | - | 2 ft above base flood elevation |
| Cut/Fill Rule | - | Balanced - no net loss of flood storage |
| Engineer Certification | - | Oregon PE - no-rise required |
Highlighted rows indicate differences between cities.
Gresham FAQ
Is my property in a flood zone in Gresham?
Check FEMA flood maps or contact Gresham Development Services. Johnson Creek and tributaries are primary flood hazard areas.
Can I build in a flood zone in Gresham?
Yes, with strict requirements: elevation above the base flood elevation, flood-resistant construction, and an elevation certificate.
Troutdale FAQ
Is my Troutdale property in a flood zone?
Check the FEMA Flood Map Service Center (msc.fema.gov) for Troutdale's effective Flood Insurance Rate Map. Special Flood Hazard Areas cover about 3% of the city — mostly along the Sandy River, Beaver Creek, low-lying industrial areas north of I-84, and near Edgefield. Property owners with federally backed mortgages in an SFHA must carry flood insurance.
What is the freeboard requirement in Troutdale?
Troutdale Development Code Chapter 14 requires the minimum finished floor elevation (including basement floor) for all new or substantially improved residential structures in the Flood Management Area to be at least 2 feet above the base flood elevation shown on the FEMA FIRM.
Do I need a Troutdale floodplain permit?
Yes. Any 'development' in the Flood Management Area — including new construction, substantial improvement, fill, grading, or paving — requires a Floodplain Development Permit administered by the Troutdale Floodplain Manager in Community Development. The project must also meet balanced cut/fill, 2-foot freeboard, and Oregon-PE no-rise certification under Chapter 14.
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