Why do you need a backflow preventer?

WVI is certified in accordance with the BC Water & Waste Association (BCWAA) to test irrigation backflow preventers throughout Metro Vancouver and all of British Columbia. The primary purpose of a backflow preventer is to prevent the water in your main water supply from flowing in a reverse direction. Most irrigation systems are directly connected to your municipal water supply and in most cases the municipality requires by code a backflow preventer for irrigation systems. Why? The biggest reason is to prevent contaminants or fertilizers from being drawn back into the potable water supply due to backpressure and/or back-siphonage.

Backpressure occurs when the downstream pressure (ex. your irrigation system) is greater than the water supply (ex. city water supply). Feed pumps, boilers, and elevated tanks can cause backpressure.

Back-siphonage is backflow caused by negative pressure in your irrigation or potable water system. A break in a City main line or increased demand due to fire fighting can cause backpressure.

The health and safety to all those connected to the water source are at risk if compliance is not met when it comes to cross connection control. For this reason, backflow testing is strongly recommended and by some cities required on an annual basis.