Backflow Education
What you need to know
Backflow is one topic that is easily understood if you are involved closely with the water industry, but many consumers do not understand the importance of the topic or how it relates to them and their surrounding community.
Terms & Definitions
Backflow - Backflow is an undesirable reverse flow of a substance (water or otherwise) through a cross connection into the drinking water system. A backflow can contaminate either the customer’s drinking water system within a building or the public drinking water system in the street. Back flows can be caused in one of two ways: back-siphonage or back-pressure.
Cross-Connection - A cross connection is a physical connection between a drinking water system and some other environment which could allow a backflow of contaminants to enter the drinking water. This could be a pipe connecting a customer’s drinking water system to the heating/cooling system, fire system or irrigation system.
Why do backflow preventers need to be tested every year?
The backflow preventer is a mechanical device that needs maintenance just like a car. The annual test indicates if the internal check valves and mechanics are working properly and protecting your water.Where are cross connections found?
Cross connections are found in all plumbing systems. It is important that each cross connection be identified and evaluated as to the type of backflow protection required to protect the drinking water supply. Some plumbing fixtures have built in backflow protection in the form of a physical air gap. However most cross connections will need to be controlled through the installation of an approved mechanical backflow prevention device or assembly. Some common cross connections found in the plumbing and water system include:- Wash basins and service sinks
- Hose bibs
- Irrigation sprinkler systems
- Auxiliary water supplies
- Photo developing equipment
- Boilers
- Swimming pools
- Solar heating systems
- Fire sprinkler systems
Why are backflow preventers needed?
Backflow preventers are designed and installed to prevent the flow of water backwards through a pipe. Two commonly required backflow preventers are the double check valve assembly (DC) and the Reduced Pressure Zone Assembly (RP) both of these protect your public utility drinking water systems from backflow created by back siphonage and backpressure.The reduced pressure zone assembly or RP backflow preventer is used for health hazards such as sewage, medical fluids, and chemicals.
The double check or DC is used to protect the utility system from non-health hazards such as odor, color, and taste. These include well water, swimming pool water or nontoxic industrial fluids such as dye or food products.
Other Backflow Terms
- PVB-Pressure Vacuum Breaker
- DCDA- Dual Check Detector Assembly
- RPDA – Reduce Pressure detector assembly
- AVB – Atmosphere Vacuum Breaker
