OR SB498

Expands the definition of "historic home" from dwellings built between 1850-1945 to any single-family dwelling constructed before January 1, 1974

Allows property owners in rural residential zones to build a new single-family dwelling and convert the existing historic home into an accessory dwelling unit (ADU)

Requires the lot to be at least two acres, located outside urban growth boundaries and urban reserves, and the ADU must meet sanitation and wastewater requirements

Prohibits subdividing the property to separate the new dwelling from the ADU, rebuilding the ADU if lost to fire, or expanding the ADU beyond 120% of the original historic home's square footage

Counties retain authority to require shared water supply between dwellings and impose additional conditions of approval