Is There Less Water in Higher Grades of Gasoline? UNVERIFIED
Understanding the water content in different gasoline grades.
There's no confirmed answer to this yet. Below is what is and isn't known — we'd rather be honest than invent a number or a spec. This becomes a full guide the moment we can confirm it; for now, your owner's manual is the authority on your specific car.
Water Content in Gasoline Grades
Gasoline typically contains a small amount of water, but this is not directly related to the octane rating of the fuel. All grades of gasoline (87, 89, 91, 93) are refined to meet certain standards, and the presence of water is generally minimized during the refining process.
Water can enter gasoline through condensation, leaks, or contamination, but reputable fuel suppliers take steps to prevent this. Therefore, the octane rating itself does not determine the water content in gasoline.
What Isn't Confirmed
There is no specific evidence to suggest that higher octane fuels have less water than lower octane fuels. The quality control processes for fuel can vary by supplier, but this is not inherently linked to the octane rating.
Where to Verify
For more information on fuel quality and standards, you can refer to the U.S. EPA's Fuel Economy website or consult your vehicle's owner's manual for guidance on fuel selection.
EPA/DOE FuelEconomy.gov data retrieved 2026-07-24.