double check valves

A double check valve is a device installed in plumbing and fire protection systems to prevent contaminated water from flowing backward into the clean water supply. It contains two separate check valves that work together; if one fails or leaks, the second prevents reverse flow. This setup enhances safety by ensuring that pollutants or hazardous substances cannot flow back into the potable water system, protecting public health and maintaining the integrity of clean water sources. Double check valves are commonly used where cross-connection control is necessary to prevent backflow contamination.