Josephine County, OR Environmental Rules: Flood Elevation Requirements (2026)

090(B) sets construction standards for flood hazard areas where base flood elevation (BFE) data exists. Subsection (B)(1)(a) requires new construction and substantial improvement of any conventional residential structure to have its lowest floor, including any basement, elevated one foot or more above BFE; fully enclosed space below that floor is prohibited unless fitted with at least two flood vents totaling one square inch of opening per square foot of enclosed area, with vent bottoms no higher than one foot above grade. Manufactured homes placed or substantially improved outside an existing park, or in a new or expanding park, must sit on a permanent foundation with the lowest floor 18 inches above BFE and be securely anchored against flotation, collapse and lateral movement under (B)(2)(a); in an existing park within zones A1-30 or AE, the home may instead sit on reinforced piers at least 36 inches above grade under (B)(2)(b).

Nonresidential buildings may floodproof to BFE instead of elevating, if a registered engineer or architect certifies the design under (B)(3); floodproofed buildings are rated for insurance as if one foot below their floodproofed level. Recreational vehicles are exempt if they stay under 180 consecutive days or remain licensed, wheeled and connected only by quick-disconnect utilities under (B)(4). 030(B).