Pasadena, MD & Nearby Areas 
Plumbing systems are fairly complex and have many more components than most people realize. One essential component you find in many residential and commercial plumbing systems is a backflow prevention valve. This article will explain how backflow prevention works and what purpose different types of backflow valves serve in protecting freshwater supplies and buildings.
How Backflow Prevention Works
The purpose of a backflow prevention device is to ensure that wastewater does not make its way into your home’s clean water supply. They ensure water can only ever flow in the direction it should. There are several different types of backflow valves, but they usually have either a diaphragm that opens and closes or a spring-loaded flap or gate. The valve always stays open when water flows in the correct direction. If the water ever flows in the opposite direction from what it should, it results in the diaphragm or flap closing and blocking off the water.
Types of Backflow Prevention Devices
There are three main types of backflow prevention commonly used in residential plumbing systems, and each one serves a distinct purpose. The first type of backflow prevention valve is installed at the point where the main water line enters your home. Its purpose is to prevent water from flowing back out of your home’s plumbing system and contaminating the municipal water supply. While this kind of backflow is uncommon, it can occur if there’s a sudden drop in pressure, such as during a water main break or extensive firefighting efforts.
The second type, commonly known as an anti-siphon valve, is typically found in outdoor faucets. This device protects the building’s water supply from contaminants that could be drawn in through a hose during a pressure drop. For instance, if a hose is left on the ground and back-siphonage occurs, substances like fertilizers, pesticides, mud, or other debris could be sucked into the freshwater pipes, posing a significant health risk.
The third type is a sewage backflow preventer, which a professional plumber installs where your home’s underground sewer line connects to the municipal sewer system. This device ensures that sewage can’t flow backward into your house, which could cause backups through drains and fixtures. Although rare, this issue can arise when heavy rainfall overwhelms the municipal sewer system. The sewage backflow preventer features a flap that normally remains open, allowing wastewater to flow out. If sewage begins to flow backward, the flap closes to block the pipe, preventing potentially hazardous sewage from entering your home.
Are Backflow Prevention Devices Required?
The requirement for backflow prevention devices depends on local plumbing codes, your home’s age, and your property’s specific features. In Maryland, newer homes are generally required to have a backflow prevention valve installed on the main water line. Older buildings are typically exempt unless their plumbing system is being replaced or the property includes features like a swimming pool or underground sprinkler system.
Federal plumbing codes mandate anti-siphon valves on all outdoor hose bibs and faucets in newer homes. However, local codes can vary; some areas may have more lenient requirements. Regardless of local regulations, installing anti-siphon valves is strongly recommended. These devices provide additional protection for your drinking water, reducing the risk of contamination and ensuring your water supply remains safe.
Sewage backflow prevention valves are sometimes required under local plumbing codes, but these requirements are less common. Even if not mandatory, installing a sewage backflow preventer is a wise precaution, especially if your home has a basement below the level of the nearest sewer manhole. In such cases, a sewer system overload could cause sewage to flow back into your home, leading to significant damage. If your basement floor is above the manhole and you do not have any below-grade plumbing, you are at a lower risk since sewage would typically escape through the manhole rather than backing up into your home.
Contact Your Local Pros
Since 2016, Priority Plumbing & Drain has been serving the residents of Pasadena, MD, and the surrounding areas. We are expert plumbers who can install and maintain backflow prevention valves to protect your home’s fresh water supply. We can also help you with all your repiping, leak detection, and drain cleaning needs. Contact us today to schedule an appointment with one of our experienced plumbers.
