How do backflow preventers work?

How-does-a-backflow-preventer-work

Backflow preventers systems are designed to keep harmful contaminants from getting into the municipal water supply. These systems are required for commercial properties and businesses may have more than one backflow valve. 

What is backflow?

Water that comes into a building from main water supply should only flow in one direction into the building. However, sometimes water pressure changes can cause water to flow back into the main water supply this is called backflow. When this happens contaminants can backflow into the city’s clean water supply. This is why backflow preventer valves are required in all commercial buildings. 

What is a backflow preventer valve?

A backflow preventer is a device designed to prevent water from flowing back into the clean water supply. The valve does not allow water to backflow even if there are water pressure changes in the plumbing. Because of this, backflow preventer systems are required to be inspected and tested annually by plumbers who are certified to test these types of systems.

Types of backflow preventers

There are a few different types of backflow preventer valves that are used in commercial buildings. A business can have one or more backflow systems depending on the business.

Domestic Backflow Preventer – These are standard in commercial properties and prevent any water used in the business from seeping back into the clean water supply. This includes any contaminants that may be used in the business. 

Fire Suppression Backflow System – Many businesses have fire protection systems that have sprinklers ready in case of a fire. This system has water that is pressurized and ready to be used instantly in the sprinklers in the event of a fire. However, this water is stagnant and bacteria can grow in these pipes. This water can be potentially harmful if it were to backflow into the city’s drinking water supply. Buildings that have fire suppression or fire protection systems are required to have a fire suppression backflow system to keep this water from seeping back into our clean drinking water.

Irrigation System Backflow – Commercial properties often have irrigation systems for landscaping. Many businesses use non-potable water for irrigation so it is essential to have an irrigation backflow system.

Backflow Testing Requirements:

All backflow valves need to be inspected and tested every year. Typically businesses or property owners are notified by the city when their inspection is due. It is up to the business to schedule the inspection with a certified plumber. TLC Plumbing has certified plumbers who can perform these inspections for your backflow systems. If your backflow system is due for an inspection call TLC today for an appointment or schedule online.


TLC has a dedicated team of certified plumbers that focus on commercial and industrial plumbing systems. Schedule your inspection today.


TLC’s Commercial Services Team is dedicated to meeting the needs of businesses in Albuquerque and surrounding areas. We offer a wide variety of services for all types of businesses and facilities including 24-hour emergency repairs for plumbing, heating, cooling, and electrical services.