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Backflow prevention devices are used to protect water supplies from contamination or pollution. Backflow occurs when a drop in pressure in the potable (drinkable) water supply (such as unusually high usage, broken pipes or frozen pipes) allows water from other sources to be drawn into the potable system.


Backflow preventers come in many shapes and sizes but the two main devices used in a residential setting is the Double-Check Valve and the Reduced Pressure Backflow Device (RP). The difference between the two is the level of protection, with the RP being the higher. SOS Plumbing can install whatever device your situation calls for.


Double Check valves are commonly used where irrigation lines tee off of the main water service to a house and protects against back siphoning from underground sprinkler systems.


RP devices are used when there is an alternate source of water on your property, such as a well or Irrigation District water. This device must be placed as close to the water meter as possible, above ground in an insulated box to prevent freezing. If the alternate source of water is cross-connected with your potable water supply after the device located at the meter, another RP device is required at the cross connection (for example, using both city water and Irrigation District water in a sprinkler system.


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