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Corvallis, OR Environmental Rules: Flood Zones (2026)

Significant Restrictions

Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

FEMA flood zone rules in Corvallis, OR, also called floodplain regulations or special flood hazard area (SFHA) rules, determine flood insurance requirements and elevation standards for new construction.

Key Facts

Flood hazard area: 100-Year Floodplain (FEMA FIS, 6-2-2011)
Permit required: Floodplain Development Permit, before development
Floodplain Administrator: City Engineer
Regulatory Floodway: No fill, construction, or fences allowed
Enforcement tools: Stop Work Order, citation, civil action
Records on file: 1245 NE Third St. & 501 SW Madison Ave.

FEMA Flood Zone Lookup

FEMA assigns every parcel in the U.S. a flood-hazard designation on its Flood Insurance Rate Maps (FIRMs). Zones starting with A or V are high-risk Special Flood Hazard Areas where federally backed mortgages require NFIP flood insurance. Zone X indicates moderate-to-minimal risk, where insurance is optional but often recommended. Your specific zone determines insurance cost, build elevation, and permit requirements in Corvallis, OR.

Zone	What it means	NFIP required?
A	High-risk flood area; 1% annual chance flood, no detailed analysis.	Yes
AE	High-risk; same as A but with established Base Flood Elevations.	Yes
AH	High-risk shallow flooding (1-3 ft), usually ponding.	Yes
AO	High-risk shallow flooding (1-3 ft) with sheet flow on sloping terrain.	Yes
V	High-risk coastal zone subject to wave action (no BFE).	Yes
VE	High-risk coastal zone with wave action and established BFEs.	Yes
X (shaded)	Moderate risk; between the 1% and 0.2% annual chance flood.	Recommended
X	Minimal risk; outside the 0.2% annual chance floodplain.	No

Look up Corvallis, OR on the FEMA flood map

FEMA maps update periodically; verify zone before buying flood insurance or building.

Summary

In the City of Corvallis, any development in the Special Flood Hazard Area, the mapped 100-Year Floodplain of the Willamette River, Marys River, Millrace, and local streams, needs a Floodplain Development Permit before work starts. Land Development Code Chapter 4.5 bars new construction, fill, and even fences from encroaching on the Regulatory Floodway, and the City Engineer serves as Floodplain Administrator, reviewing every permit against the FEMA Flood Insurance Study for Benton County.

4.5.20.01 Natural Hazards that are Subject to this Chapter. a.These provisions apply to public and private properties in the Special Flood Hazard Area (100-Year Floodplain) of rivers and local streams; ... 4.5.50.01 Floodplain Development Permit. The Developer must obtain a Floodplain Development Permit consistent with Chapter 2.11 - Floodplain Development Permit, prior to initiating Development activities in any Special Flood Hazard Area established through Section 4.5.20.01. ... 4.5.80.01 Encroachments. Development encroachments are not allowed within the Regulatory Floodway. Encroachments include fill, New Construction, fences, Substantial Improvements (except as provided in Section 4.5.80.03.c, below), and other Development.

View official code

Full Breakdown

Corvallis's Special Flood Hazard Area, defined in Land Development Code Section 4.5.20.01 as the 100-Year Floodplain of rivers and local streams, is mapped on the Corvallis Natural Hazards Map using the Federal Emergency Management Agency's Flood Insurance Study for Benton County and Incorporated Areas, dated June 2, 2011, with its accompanying Flood Insurance Rate Maps kept on file at the City Engineer's office at 1245 NE Third Street and at the Development Services Division at 501 SW Madison Avenue. Under Section 4.5.50.01, a developer must obtain a Floodplain Development Permit under Chapter 2.11 before any development activity begins in that area, and every Land Division, Excavation and Grading Permit, Building Permit, and utility permit application on a parcel touching a mapped or unmapped Special Flood Hazard Area must identify the hazard area's location under Section 4.5.50.02.

Inside the Regulatory Floodway, the most restrictive zone, Section 4.5.80.01 bars encroachments outright, including fill, new construction, and fences, with narrow exceptions for bridges, infrastructure, and water-dependent uses backed by an engineer's hydrologic analysis showing no rise in flood levels. The City Engineer holds the title of Floodplain Administrator under Section 4.5.60.01 and reviews every permit application, interprets disputed floodplain boundaries, records elevation certifications, and inspects Special Flood Hazard Areas for unpermitted work, reporting non-complying conditions for enforcement.

Violations & Fines

Development that starts in a Corvallis Special Flood Hazard Area without a Floodplain Development Permit, or that places fill or a structure inside the Regulatory Floodway, is a Code violation the Floodplain Administrator inspects for under Section 4.5.60.01(b)(15): the Administrator's field report can lead to a Stop Work Order, a citation, or the City pursuing civil legal proceedings against the property owner until the work is brought into compliance or removed.

Frequently Asked Questions

Does a Corvallis property in the floodplain need a special permit?

Yes. Land Development Code Section 4.5.50.01 requires a Floodplain Development Permit under Chapter 2.11 before any development activity starts in a mapped or unmapped Special Flood Hazard Area, and the application must show the hazard area's location under Section 4.5.50.02.

Can someone build a fence in Corvallis's Regulatory Floodway?

No, not without a narrow exception. Section 4.5.80.01 bars encroachments, including fences, fill, and new construction, in the Regulatory Floodway, allowing only bridges, infrastructure, or water-dependent uses supported by an engineer's analysis showing no increase in flood levels.

Who administers Corvallis's floodplain rules?

The City Engineer, appointed Floodplain Administrator under Section 4.5.60.01. The Administrator reviews permit applications, interprets floodplain boundaries against the FEMA Flood Insurance Study for Benton County, records required elevation certifications, and inspects the Special Flood Hazard Area for development that proceeded without a permit.

What happens if Corvallis finds unpermitted work in the floodplain?

Under Section 4.5.60.01(b)(15), the Floodplain Administrator's periodic inspections generate a field report on non-complying conditions, and the City can respond with a Stop Work Order, a citation, or civil legal proceedings until the property owner brings the work into compliance.

Sources & Official References

Other rules in Corvallis

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All Corvallis rules

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