What is a key indicator of a backflow prevention device’s failure?

A key indicator of a backflow prevention device’s failure is the presence of contaminants in potable water. When a backflow prevention device is functioning correctly, it prevents the reverse flow of water, which includes any contaminants or pollutants, into the potable water supply. If contaminants are detected in the drinking water, it signals that the device has likely failed in its function, allowing unclean water to enter the system. This is critical because the primary purpose of backflow prevention devices is to protect the integrity of potable water systems from contamination, thereby safeguarding public health.

The other options, while related to issues in plumbing and water systems, do not directly indicate that a backflow prevention device has failed. Frequent repairs needed on plumbing might suggest general maintenance issues but do not specifically reveal backflow failure. Low water pressure can result from various factors not necessarily linked to backflow prevention devices. Increased maintenance costs could stem from various plumbing issues and do not provide a direct indication of backflow prevention failure. The identification of contaminants is the most definitive sign that a backflow prevention device is not functioning as intended.