Backflow preventers are installed on clean water supply lines to prevent contaminated water from entering clean or potable lines. Ensuring that you have a backflow preventer in place is important for keeping a city’s drinking water uncontaminated and safe to drink.
This article will help you understand when preventers are required and what your different options are.
What Do Backflow Preventers Do?
High pressure is used in water systems to ensure that water flows in only one direction through your house. But a break in this pressure can cause water to trickle back and enter the potable system, which then gets dispersed throughout the system. That’s why many cities and states require the use of backflow preventers.
Backflow preventers help keep drinking water safe for people all across a community, including you and your family. Failing to have one can also pose a threat to the environment.
When Are Backflow Preventers Required?
Backflow preventers are most common in commercial situations. However, some states require that homes also have backflow preventers in place. This is especially the case in new subdivisions or planned communities, although the responsibility to put a system in place is usually left to the builder and not the homeowner.
There are also certain situations in which backflow preventers are common because installation requires a clean water cross-connect.
Large boilers
Boilers operate with certain levels of pressure, but if the pressure becomes too high it can affect the overall pressure of the water system and cause backflow issues.
Irrigation systems
These types of systems, including extensive sprinkler systems, pose a threat by increasing the risk of a clean line being exposed to fertilizers and pesticides.
Fire suppression systems
This can cause pressure differences which result in siphoning and, thus, the contamination of clean drinking water.
Types of Backflow Preventers
There are many types of backflow preventers available, with various applications.
Approved Air Gap
A regulated, physical separation between the end of a water supply outlet and a receiving vessel. Requires a diameter that is at least twice that of the water supply outlet, and no less than 1".
Double-Check Backflow Assembly (DC)
Mechanical backflow preventers that require annual testing by specialists. Contains two spring-loaded check valves and a shutoff valve at each end. Should be used only on non-health hazards.
Reduced-Pressure Principle Backflow Assembly (RP)
Similar to DC and also testable, but hydraulically operated. Can be used on health or non-health hazards.
Pressure Vacuum Breaker Assembly (PVB)
Similar to above with spring-loaded air inlet valve on the discharge side of the check valve. Can be used to isolate health or non-health hazards, but must be installed 12" above the highest downstream water discharge. Only effective against back-siphonage and most commonly used on lawn sprinkler systems.
Atmospheric Vacuum Breaker (AVB)
Mechanical but non-testable. Most commonly installed by a manufacturer or
contracted installer on equipment that uses potable water, such as dishwashers,
soap dispensers, faucets, and deep sinks.
Hose Bibb Vacuum Breaker
A small and inexpensive device with a hose connection that can be attached in situations where a hose presents a threat of contamination. Can’t be used under continuous pressure.
What Is the Difference Between Backflow Preventers and Backwater Valves?
Unlike backflow water preventers that prevent sewage water from entering the city system, backwater valves prevent sewage water from entering an individual system. These devices are usually inexpensive and installed on private sewer service lines. They are most common in homes instead of commercial settings, meaning their installation and maintenance is usually the responsibility of a homeowner.
Winterizing Backflow Preventers
It’s common practice to winterize above-ground backflow preventers, especially in colder areas. These systems are typically found connected to sprinkler systems. Taking a few short steps to prep your system for winter can prevent damage and potentially expensive repairs.
Step 1. Shut off water
The first step to ensuring your system is winterized is shutting off the water to your sprinkler system. Do this at the main valve or stop-and-waste.
Step 2. Drain
Use a flat-head screwdriver to drain the water from the backflow.
Step 3. Adjust valves
Give valves a quarter turn to make sure they are neither completely open nor completely shut.
Step 4. Insulate
If you live in a colder climate, consider insulating your pipes with pipe insulation. After you’ve applied the insulation, wrap around it with heavy-duty, weather-resistant tape.
Understanding the rules and regulations of backflow systems can help ensure you stay within city guidelines. It’s also important for ensuring safer drinking water for you and your community, in addition to creating a cleaner environment.
Product Compliance and Suitability
The product statements contained in this guide are intended for general informational purposes only. Such product statements do not constitute a product recommendation or representation as to the appropriateness, accuracy, completeness, correctness or currentness of the information provided. Information provided in this guide does not replace the use by you of any manufacturer instructions, technical product manual, or other professional resource or adviser available to you. Always read, understand and follow all manufacturer instructions.