When water enters your home from the city water supply line, it should only flow in one direction. However, backflow can occur due to pressure changes or during events such as a fire hydrant being opened for use.
This is where backflow prevention comes into play. Backflow prevention is necessary because it helps ensure that chemicals, toxins, and debris don’t pollute the clean water lines.
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Water Pressure Changes
Backflow prevention is a necessity in multi-family residential buildings, commercial properties, and industrial facilities. It protects the municipality’s water supply from accidental contamination caused by the backward flow of contaminated wastewater into the clean drinking water line.
However, a backflow preventer isn’t required in single-family homes. This can be a huge problem for homeowners who experience backflow incidents. Backflow isn’t just a nuisance to deal with, it poses a serious threat to the health and safety of your family.
Thankfully, there are ways you can tell if your backflow preventer isn’t working properly. One of the most common signs that backflow is a problem is changes in your home’s water pressure.
Backflow occurs when the pressure in your home drops, which allows the backward flow of contaminated water into your clean water line. This can occur for a variety of reasons, including leaks, plumbing problems, or back pressure from irrigation systems or power washers.
Water backflow can also happen when a back pressure valve in your home is open. This is usually the case with older models of backflow prevention devices. Newer models of backflow preventers feature a double-chamber system.
These valves are more sophisticated than the old plate and ball valves that were found in most homes and gas stations. The double-chamber backflow preventers are much more durable and require less maintenance than the old models.
Changes in your home’s water pressure can be a sign of backflow, but they’re often difficult to detect. Conventional pressure-monitoring equipment may not pick up the reduction in water pressure, especially if it’s localized or if it’s intermittent. It’s also possible that the low water pressure is due to a line break or flushing and not backflow.
Even if you don’t see any symptoms of backflow, it’s important to contact a professional as soon as possible to prevent cross-contamination. Unprotected backflow incidents have been known to cause outbreaks of hepatitis A, gastrointestinal issues, stomach aches, and even death. If you don’t want to risk your family’s health, you should call a licensed plumber as soon as possible to service your backflow prevention device.
Unprotected Cross-Connections
As we learned from the water contamination event in Flint, Michigan, backflow can be a major problem for your local drinking water supply. It can contaminate the entire system if it occurs in a high-risk area and can be hard to identify and correct.
To protect against this, backflow prevention programs require installing testing devices and conducting surveys of consumer water use on residential or commercial properties. These surveys are designed to identify potential backflow hazards and the presence of unprotected cross-connections.
A cross connection is any point where a non-potable system or equipment connects with your plumbing water line. This can include a garden hose that is submerged in a pool or bucket of chemicals, or it can be as complex as a boiler feed line connected to bottom-fed tanks or other industrial systems.
If a cross connection is unprotected, it can allow the backflow of contaminated water into the plumbing system during a pressure change caused by either back siphonage or back pressure.
This can contaminate your home or business plumbing as well as your municipal water supply. Typically, the contaminant is bacteria or other microbes, but it can be anything from detergent to heavy metals.
In the case of a municipality, contamination can lead to a dangerous situation where citizens are told not to drink the water until it has been tested and found safe. This is why, in addition to requiring backflow preventers, most public water suppliers require periodic surveys and tests of these devices on their customer’s property.
Backflow prevention is the final and often only line of defense against contamination within your plumbing water distribution system. Since these devices are mechanical, they have internal seals, springs, and moving parts that can become damaged or worn over time. For this reason, they need to be regularly tested and cleaned by certified testers with proper gauge equipment to ensure they are working properly.
If you have an unprotected cross-connection on your property, it is important to have a backflow prevention device installed by a licensed plumbing contractor. This will help prevent contaminants from entering your plumbing and contaminating the municipal water supply in the worst-case scenario.
Your backflow preventer will often be a reduced-pressure principle assembly (RPZ) or a hose bib vacuum breaker with a double-check valve assembly. These assemblies are effective against back pressure and siphonage and are generally cheaper than other backflow preventers.
Water Leaks
Backflow prevention systems help ensure that dirty water doesn’t flow back into your plumbing pipes and contaminate your clean drinking water. The devices are installed between your home’s water supply link and anything that might pollute your water, such as your lawn sprinkler system, restaurant kitchen hose, or car wash water. If your backflow device starts to malfunction, you’ll notice a sudden drop in water pressure at the house faucets or showerheads.
Most homes, commercial buildings, and industrial properties have backflow preventers installed in their plumbing systems. These are required to protect the public water supply from accidental contamination by non-potable water, solids, and gasses. Backflow prevention is especially important for commercial property owners using their building’s plumbing for hot tubs, hair salons, restaurants, and car washes.
These types of properties often have a lot of cross-connections that could potentially siphon water back into the municipal water supply. A garden hose submerged in a swimming pool, hot tub or car radiator, a pesticide sprayer, or a fertilizer sprayer could all be used to contaminate the public water supply with toxins, bacteria, or even sewage. The backflow preventer helps to stop this contamination by ensuring that the water is only drawn from the city’s clean drinking water.
One of the most common signs that a backflow device is failing is if it begins to leak water around the valve body or protective covering joint. This is usually due to the buildup of debris in the valve’s internal components or from a faulty seal. If the problem is left untreated, it may eventually lead to a complete failure of the device.
Many kinds of backflow preventers exist, including air gaps, reduced pressure principle backflow assemblies, double-check valves, and pressure vacuum breakers. All of these devices serve a similar purpose but have varying levels of effectiveness and protection from back siphonage.
Depending on your backflow preventer type, some will be more prone to problems than others. Your certified backflow tester will know what type of device you have and the best ways to inspect it for possible issues that could affect its performance.
Damaged Valve
When water valves in engines wear out due to age or mishandling, engine failure results. When this happens, replacing or repairing the damaged parts can cost a lot of money. The same is true for backflow preventers that can be affected by damage and failure. Keeping up with the routine maintenance of these devices can help minimize problems and costs.
One way to determine if backflow prevention needs attention is when you notice contaminated drinking water. The water may be yellow or brown in color, have a sulfur smell or taste like rotten eggs. If this is the case, it’s time to call a plumber to clean and sanitize your backflow system and check for rusty water pipes.
Some backflow preventers require special tools to repair. These are usually tools that have been fabricated or purchased from the backflow manufacturer specifically for a certain model of the assembly.
A repair technician must determine if the backflow preventer requires these special or standard hand tools before beginning the repairs. Having the correct tools in place before starting a repair is important because it can make or break the outcome of the backflow preventer repair.
In addition to the proper repair tools, it is important to understand the process for repairing a backflow preventer assembly. It is vital that the repair technician correctly removes the components from the backflow preventer body and evaluates their condition. It is also critical to know which component caused a field test failure so that the repair can be done properly.
For example, if a check assembly has failed because the disc is not sealed to the seat, the repair technician needs to be sure that the disc has the right shape and profile. Changing the seat shape or profile can alter the assembly’s operation and void the original factory approval if the repair is made by changing the seat shape or profile.
Once all the repaired components are placed back into the backflow preventer body, they must be pressurized. This can be done by slowly opening the inlet shut-off valve while the downstream shut-off valve remains closed. If the inlet valve is turned on too quickly, it can cause pressure fluctuation, damaging the components.
After all the components are pressurized, any accumulated air must be removed from the assembly. This can be accomplished through the use of air bleeds, air screws, or test cocks that are located on various models of backflow prevention assemblies.
