What is backpressure backflow?

Backpressure backflow occurs when the downstream side of the piping system is greater than the supply pressure in a public system or customer’s potable water system. Backpressure can result from an increase in downstream pressure, a reduction in the potable water supply pressure or a combination of both. Pumps can create increases in downstream pressure, temperature increases in boilers, etc. Reductions in potable water supply pressure occur whenever the amount of water being used exceeds the amount of water being supplied, such as during waterline flushing, firefighting, or breaks in the water mains.

Show All Answers

1. Why does the City of Forest Lake need a Cross-Connection and Backflow Testing Program?
2. What is backflow?
3. What is a backflow prevention assembly or device?
4. What is the process for installing/replacing a backflow prevention assembly?
5. Why do backflow prevention assemblies need to be tested?
6. How often does the backflow prevention assembly need to be tested?
7. How can I contact a licensed backflow assembly tester/rebuilder?
8. When requesting a test for my backflow prevention assembly, how much should I expect to pay for this service?
9. What type of document needs to be returned to the city as proof that testing of the backflow prevention assembly was completed?
10. How can I verify that testing of my backflow prevention assembly has/has not been completed?
11. Does a lawn irrigation system require a backflow prevention assembly?
12. How long does a backflow prevention assembly last?
13. What is considered a “potential hazard” to the potable water supply?
14. Has the City of Forest Lake process for permitting or overseeing the inspection of new, relocated or repaired backflow prevention changed?
15. What is backpressure backflow?
16. What is back-siphonage?
17. What is a cross-connection?