Which of the following conditions signals a malfunctioning OSSF?

Water pooling above ground is a clear indicator of a malfunctioning On-Site Sewage Facility (OSSF). When water accumulates on the surface, it can signify that the system is unable to effectively treat and disperse the wastewater underground. This pooling may occur due to a variety of reasons, such as an overloaded system, clogged drain fields, or a failure in the effluent distribution. Such conditions not only point to potential failures in the system's design or maintenance but also pose health risks and environmental concerns due to possible contamination of surrounding areas.

In contrast, the other options present situations that would not indicate a malfunction. The absence of odors typically suggests that the system is functioning correctly, as foul smells are often associated with improper operation or backing up of wastewater. Similarly, if wastewater is fully treated, it implies that the treatment processes are working as intended, which is a sign of a properly functioning system. Lastly, the statement that all systems are functioning normally also reflects a healthy operational state, highlighting that none of those scenarios would suggest a malfunction.