What Is a Backflow Preventer and Do You Need One?

Backflow is the reversal of water flow in a plumbing system — contaminated water flowing backward into the clean supply. It happens when there's a sudden drop in supply pressure, such as during a water main break or heavy firefighting demand. Without a backflow preventer, that reversal can pull irrigation water, pool water, or chemical-treated water back into your home's drinking supply.

Michigan plumbing code requires backflow prevention devices on irrigation systems, boiler systems, fire suppression systems, and any connection between the potable water supply and a non-potable source. If you have an in-ground sprinkler system and no backflow preventer, you're likely out of compliance — and your drinking water is at risk.

There are several types of backflow preventers. A pressure vacuum breaker (PVB) is the most common for residential irrigation. A reduced pressure zone (RPZ) device is required for higher-hazard applications like boilers and chemical injection systems. The right device depends on the application and the level of hazard.

Backflow preventers require annual testing in most Michigan municipalities. The test verifies that the device is functioning correctly and documents compliance. We perform backflow testing and certification across all 7 Metro Detroit locations.

If you're not sure whether your property has a backflow preventer or when it was last tested, call us at 313-427-4780. We'll assess your system and bring it into compliance.