What is a common sign of inadequate tank maintenance?

A common sign of inadequate tank maintenance is leaking or corroded fittings and hoses. These issues indicate that the tank and its components are not being properly cared for, which can lead to serious safety hazards, including spills and leaks that can damage the environment and create dangerous driving conditions. Proper maintenance should include regular inspections for signs of corrosion, wear, or leaks to ensure that everything is functioning as intended and to prevent potentially hazardous situations.

The other options represent signs of good maintenance and operational efficiency. Properly functioning valves indicate that the tank system is operating correctly and safely. Increased fuel efficiency suggests that the tank and its associated systems are performing optimally, reflecting good maintenance practices. Clear tank visibility means that the interior of the tank is well-maintained and free of unnecessary residues or blockages, which is also a sign of adequate upkeep.