The water crisis in Flint made national news when it was found that the public water supply was contaminated with hazardous levels of lead. The polluted water supply was used and ingested daily by 100,000 individuals resulting in several deaths and hundreds of health-related illnesses. This catastrophe has brought to light the need for safety measures to be put in place to protect the public water supply, especially here in Michigan. One-way local municipalities, including Plymouth and Canton are doing this is by requiring backflow devices to be installed and inspected regularly on fixtures connecting to public water sources in both commercial and residential applications.

Preventing water backflow is fundamental. Without a backflow preventer in place water is free to flow in either direction, which as seen in Flint can result in significant contamination. Residents throughout Canton may have noticed recently that the city is rolling out regulations that require residential backflow devices be tested once every five years. As of July 2022, Canton is on the second roll out of five, with three more scheduled to be completed by 2025. To better understand the importance of these safety measures and regular testing, we have created a short guide on backflow terminology and answers to frequent questions.



The term backflow is used to represent the reversal of flow into the water supply. When a municipal water source is used to provide water to your home and in turn to your irrigation system, it is crucial to install a backflow prevention device. There are points within a residential water supply where the potable water connects with the non-potable, for example dishwashers, washing machines, and irrigation systems. The cross-connection points where these appliances meet must be designed in a manner that backflow between does not occur.

Direct and Indirect Cross-Contamination

There are two ways contamination can occur, indirect and direct. Indirect contamination, also known as back-siphonage, occurs when high pressured fluids, gases or suspended solids move to the area where lower pressured fluids are. Think of how a straw is used, sucking into the straw creates pressure inside the straw which in turn causes liquid to come up through the straw. The same is true for systems that deliver water. If a substantial drop in pressure occurs within the water delivery system, the suction that occurs can pull unwanted materials into the water supply causing indirect cross-contamination.

Direct contamination, back- pressure is the exact opposite phenomenon. When a customer’s water pressure exceeds the pressure of the supply-side direct contamination can occur. If natural gas is forced into a potable water tank, it can move through to a faucet. Systems to consider as sources of possible direct contamination are boilers or water operated back up sump pumps.

Water Backflow Prevention Devices

Air Gap: An air gap is one of the simplest types of backflow preventers that can be installed. The air gap creates a physical separation between the potable and non-potable water ensuring they do not meet.

PVB: A pressure vacuum breaker is another commonly used backflow prevention device. A PVB will only prevent back-siphonage, otherwise known as indirect contamination. This device consists of multiple parts, the inlet shut off valve, spring-loaded check valves, test valves and an outlet shut off valve. A working PVB is a crucial component to any irrigation system to protect against backflow from the irrigation system to the home’s drinking water. The PVB protects against a drop in the home’s main water supply has a sudden drop in water pressure, resulting in negative pressure against the home’s main supply. It protects against water being sucked out of the sprinkler lines, into the main water supply, and the homes fixtures.

Other water safety devices that are used to prevent cross-contamination include double check valves, reduced pressure principal assemblies, and spill-resistant vacuum breakers. Our certified backflow testers are experienced with the new installation, replacement, repair, and testing of all backflow devices.

Reasons Backflow Preventers are Installed

The most common reason backflow devices are installed is to keep drinking water safe and free of contaminants. Not only is it important the device is installed properly it is also critical that the device stays in working order. How often testing is needed to verify the device is working will vary between municipalities as well as if the device is used in a commercial or residential application. Regular testing helps to catch device failures before they become catastrophic.

The installation of a backflow preventer is a legal requirement in most states. The states Health department may require municipalities to develop and implement programs to protect the states public water supply. Homeowners and business owners alike make incur large fines if the do not meet local water safety requirements. To avoid fines and legal ramifications it is beneficial to follow regulations set forth by local officials.

The licensed & insured, master plumbers of Horton Plumbing are certified in backflow prevention.  Whether you need a new device installed, a failed device replaced, a broken backflow repaired, or backflow test performed the team at Horton Plumbing can help.