Which of the following is a sign that a septic system might be failing?

A strong odor around the tank area is indeed a significant indicator that a septic system might be failing. This smell typically arises when sewage is not being properly broken down and contained within the system. When a septic tank is functioning correctly, any odors should be minimal and confined to the tank area. However, strong or persistent odors suggest that there may be a buildup of gases, which could indicate issues such as an overflow, blockage, or a breakdown in the system's integrity. Additionally, strong odors can hint at the potential for untreated wastewater escaping from the tank, which could pose serious health and environmental risks.

In contrast, consistent water pressure in all taps would imply that the plumbing system is functioning properly, and quick drainage of sinks and toilets suggests that the system is effectively removing wastewater. Regular maintenance of the leach field indicates that the system is being taken care of, which typically prevents failures. Hence, those options do not suggest the presence of problems, reinforcing that the strong odors around the tank area are a clear warning sign of a failing septic system.