Backflow Prevention Explained in Fewer than 130 Words
Water pressure should only flow into your home, but occasionally the distribution system can have problems with the burst of frozen pipes. This disrupts water pressure and causes water to reverse its flow.*
A backflow** prevention system aims to prevent contamination or pollution of drinking water. Backflow preventer valves (check valve) are installed in strategic locations to prevent contamination, and should be automatic. A check valve is especially important where lawn and fire sprinkler systems, swimming pools, private wells, and fountains are installed. Did you know that Federal and Maryland state laws mandate annual testing of backflow prevention devices?
Now is a great time to have your system checked by a trusted plumber.
Image credit: http://www.nwwater.com/index.php/your-water/main-system/backflow-prevention
* https://plumbingtoday.biz/blog/what-is-a-backflow-preventer-and-how-does-it-work
** https://en.wikipedia.org/wiki/Backflow