Tiny Fuel Tanks OK, But Only When Trailers Aren't Moving
Published Date: 2/19/2026
Rule
Summary
The FMCSA is updating fuel tank rules to allow small auxiliary fuel tanks (up to 5 gallons) on trailers to use gravity or siphon feeds, but only when the vehicle isn’t moving. This change helps truck trailer makers by easing a rule without hurting safety. The new rule kicks in on March 23, 2026, and anyone wanting to challenge it must act by that date.
Analyzed Economic Effects
2 provisions identified: 2 benefits, 0 costs, 0 mixed.
Allows small trailer fuel tanks to use gravity feed
If you make or own truck trailers or auxiliary fuel pumps, the rule lets auxiliary pumps with a nominal fuel tank capacity of not more than five gallons mounted on the trailer chassis frame or trailer bed supply fuel by gravity or siphon only when the motor vehicle is not in motion. This change takes effect March 23, 2026.
FMCSA says small-entity costs are de minimis
FMCSA certified this rule will not have a significant economic impact on a substantial number of small entities and said any cost savings for owners of eligible auxiliary pumps are expected to be de minimis. The agency did not quantify the savings.
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