Just about everything in California gets a smog check every two years. That includes gasoline, propane, ethanol, and natural gas powered vehicles. There are areas in California that don't get biennial smog checks, but most areas where people live, they are a requirement. Cars that are 1975 or older, and diesel vehicles 1997 or older don't get smog checks.
1.1.4 Affected Vehicles (Must be smog checked every two years)
Gasoline - 1976 model-year and newer vehicles powered solely or in combination by:
• Gasoline (Includes hybrid vehicles - beginning January 2015)
• Propane
• Natural gas
• Methanol/ethanol
Diesel - 1998 model-year and newer vehicles with a gross vehicle weight rating (GVWR) 14,000
pounds and less powered solely or in combination by:
• Diesel
• Propane
• Natural gas
• Methanol/ethanol
VC §§ 4000.1, 4000.2, 4000.3, H&S § 44011, CCR §§ 3340.5, 3340.42
1.1.5 Exempted Vehicles
• Gasoline vehicles 1975 model-year and older.
• Gasoline vehicles eight or less model-years old are exempt from the biennial inspection.
• Gasoline vehicles four or less model-years old are exempt from inspection upon change
of ownership.
• Diesel vehicles 1997 model-year and older.
• Diesel vehicles with a GVWR of 14,001 and more.
• Vehicles powered solely by electricity.
• Two-cylinder or less.
• Two-stroke (two cycle) engines, excluding rotary engines.
• Motorcycles.
Until further notice, CNG, LNG or LPG vehicles with a GVWR of 14,001 and more are
exempted.
H&S §§ 44011, 44011(a)(6), VC § 4000.1, CCR §§ 3340.5, 3340.42
